SU1303258A1 - Method of continuous casting of steel - Google Patents

Abstract

The invention relates to continuous casting of steel. The aim of the invention is to improve the quality of steel by reducing the content of non-metallic inclusions, harmful impurities and gases, and increasing the degree of absorption of micro-alloying elements. The method allows the refining and micro-alloying of steel in the tundish and the mold and consists in supplying the carrier gas through an open hollow stopper-powder injector from chemically active slags with a powder fraction of 0.3-3.0 mm with an input speed of 4-25 g / with an overpressure of a carrier gas of 0.25-2.5. 1 dw., 4 tab. e (L about N) CL 00

Description

This invention relates to metallurgy, in particular to continuous casting of steel.

The purpose of the invention is to improve the quality of steel by reducing the content of non-metallic inclusions, harmful impurities and gases, and increasing the degree of assimilation of micro-alloying elements.

The drawing shows the scheme of Ou-Juritas,

implementation of the method.

The method is carried out as follows.

In the process of continuous casting, steel is supplied to the tundish, and from it to the mold, from where the billet is drawn. With this, the refining and microalloying components in the form of a gas-powder mixture are fed into the intermediate ladle and into the jet of metal entering the mold, via a hollow injecting lock with channels.

Example I. Gas injector-stopper with fireclay plug and outlet channels 0 6 mm in the stopper plug located below the contact line of the lock pair. The casting speed is 0.5 m / min, the overpressure in the injector is 0.25 atm. Bath depth in tundish 700 mm. The slag surface in the crystallizer is calm with a slight bubbling of argon outgoing., There is no splash and emissions.

Example 2, Gas injector stopper with fireclay stopper and output channels 0 b mm in the stopper located above the contact pin of the stopper pair. Casting speed 0.8 M / M1-1NG. Bath depth in tundish 700 mm. Overpressure 1,5 atm. Intensive bubbling of metal in a tundish,

Example 3, Gas injector-stopper with fireclay stopper. The output channels of 6 mm are located above and below the contact line of the stop pair (the number of channels in the upper part is larger than in the lower part). Casting speed 0.8 m / min. Overpressure 1,5 atm. Intensive bubbling of metal in the tundish and weak bubbling in the mold,

In tab. The data on the calcium content in the finished steel and

2582

degree of assimilation depending on the processing method and powder consumption.

The study of the macrostructure of slabs treated with silicocalcium showed a decrease in chemical inhomogeneity by 1 point, axial porosity by 1.5 points and more developed zones of equiaxial crystals and disoriented den

Example 4. Treatments of liquid steel by blowing through the stopper-injector of powdery chemically active elements

Table 2 shows the data when processing liquid steel 09G2FB on continuous casting. billets (caster) powdered chemically active elements (CAE) on the example of metallic titanium and yttria. The maximum degree of absorption of titanium in steel is 70.0%, and ytt 80%. At high costs, the degree of absorption decreases to 60% for titanium and 70% for yttrium. Casting speed 058 m / min.

Example 5, Treatment of liquid steel by blowing through a lock injector with powder solid slags, Table 3 shows the results of treatment of liquid steel with solid synthetic slags. Additional desulfurization of steel in a continuous casting machine reaches 25% and depends on the consumption of solid slag mixtures.

(TSHS), casting speed 0.8 m / min.

40

An example. $. Treatment of liquid steel by blowing through the stopper-injector with slag-metal mixtures.

five

Table 4 shows the results of the treatment of liquid steel with solid slag-metal mixtures (OMS), SMC is more effective than TSS, since this results in additional micro-doping with chemically active elements and desulfurization. Casting speed 0.8 m / min.

The boundary conditions for the overpressure of the carrier gas are selected taking into account the allowable intensity of sparging of metal and slag melts of 700–1000 mm in depth. The size of the fractions of powder materials has a significant effect on the resistance of the main system and the kinetics of dissolution of particles in the melt.

0

The speed of transportation of reagents in the system correspond to the consumption of powder materials 0.15-0.5 kg / t

It is possible to introduce liquid reagents through a stopper injector due to the fact that the temperature inside the manifold of the stopper plug can be controlled. In the usual case of the casting stopper, the internal surface of the stopper is cooled with compressor air. At the same time, the temperature is set in the range of 600-800 ° C. In the absence of such cooling, the temperature sharply increases, practically to the level of liquid, steel. Under these conditions, favorable conditions are created to melt the powders, which then fall into the bulk of the metal bath in a liquid form.

When testing a method with steel purging with a gas-powder mixture (argon silicocalcium) with a reagent injection rate of 10–20 g / s and excess

argon pressure of 0.5-2.0 MPa obtained

1 2 3 4, 5

6

Comparative

7 8 9

 eleven

an increase in the degree of calcium absorption up to 40-60% and an improvement in the structure of uninterruptedly cast baud.

Claims (1)

Invention Formula The method of continuous casting of steel, including refining and microalloying in the tundish and the mold of the continuous casting machine by feeding reagents through a hollow injector stopper, characterized in that, in order to improve the quality of steel by reducing the content of non-metallic inclusions, harmful impurities and gases and increasing the degree of absorption of micro-alloying elements, refining and micro-alloying active slags and chemically active elements in the form of a gas-powder mixture with a powder fraction of 0.5-1.0 mm with a feed rate of 5-25 g / s under an overpressure of gas-carry 0,004 0,003 0,006 0,008 0,007 eleven 8 13 13 16 1 table 2 0.5 0.25 5.0 0.125 1.0 15.0 0.375 1.0 Magnesium fluoride - 0.5 to a mixture of Mg / MgF 0.56 1.0 Table 4 0,0010 0,0080,008 0,0010 0,0080,007 0,0020 0,0080,005 0.0 0.0080.008 0,0005 0,0080,007 0,0015 0,0080,005 O0,0080,008 0,0005 0,0080,007 0,0010 0,0080,006 O0,0080,008 0,0005 0,0080,007 0,0010 0,0080,006 Reag / p