RU2349413C2 - Steel continuous casting method - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention concerns ferrous metallurgy. Particularly it concerns methods of steel continuous casting on continuous-casting plant. During the method implementation it is feeding of liquid steel from ladle into intermediate ladle and then through immersible sleeve to crystallisers, forming in crystallisers sections, its withdrawal from crystallisers and cooling in area spray cooling chamber. Withdrawal of sections from peripheral crystallisers is implemented at a rate higher withdrawal rate from central crystallisers for 0.01-0.1 m/min subject to steel temperature in crystalliser, at that at reduction of metal temperature in peripheral crystallizer for 1°C in comparison with central crystalliser, withdrawal rate from peripheral crystalliser is increased by 0.01 m/min.

EFFECT: invention provides improving of continuous-casting plant productivity, cost cutting and macrostructure improving of sections.

Description

The invention relates to ferrous metallurgy, and in particular to methods for continuous casting of steel on continuous casting machines.

Known as a prototype is a method of continuous casting of steel on a multi-strand radial machine for continuous casting of billets, including feeding liquid steel from a steel ladle to an intermediate ladle and then through immersion glasses into molds, forming continuously cast billets in molds, drawing them out of the molds and cooling them to zone of secondary cooling [1].

Significant disadvantages of the method of continuous casting of steel are

- reduced productivity of continuous casting machines;

- the high cost of continuously cast billets;

- the presence of macrostructure defects in continuously cast billets.

The desired technical results of the invention are

- improving the performance of continuous casting machines;

- reduction in the cost of continuously cast billets;

- improvement of the macrostructure of continuously cast billets.

To this end, a method is proposed for continuous casting of steel on a multi-strand radial machine for continuous casting of billets, comprising supplying liquid steel from a steel pouring ladle to an intermediate ladle and then through immersion glasses to molds, forming continuously cast billets in molds, drawing them out of the molds and cooling in the secondary zone cooling, in which the drawing of the blanks from the peripheral crystallizers is carried out at a speed higher than the drawing speed from the central crystalline congestion by 0.01-0.1 m / min depending on the temperature of the steel in the mold, and when the metal temperature in the peripheral mold is reduced by 1 ° C compared with the central mold, the speed of drawing out of the peripheral mold is increased by 0.01 m / min .

The claimed limits are selected based on the following prerequisites, selected empirically. When the peripheral (extreme) continuously cast billets are drawn from the molds, the continuous-cast billets from the central molds are drawn at a speed of 0.01-0.1 m / min and the same temperature and speed conditions are ensured for the formation of high-quality continuously cast billets. At the same time, on the one hand, an increase in the productivity of casting at peripheral (extreme) streams is ensured, and on the other, a uniform and high-quality macrostructure of both central and peripheral workpieces. Experimentally, the ratio was selected: when the temperature in the mold decreases by 1 ° C, the drawing speed increases by 0.01 m / min.

The inventive casting method is implemented on a 4-groove radial caster with a mold section of 300 × 330 mm when casting steel grades st.3-5sp, st.45, 40X, E76, E76F. The temperature of the metal in the crystallizers of the peripheral (extreme) streams in the experimental melts was 1-10 ° C lower than the temperature of the metal of the central streams. The casting speed (drawing of continuously cast billets) was changed depending on the temperature of the metal in the central and peripheral molds. Temperature measurements in crystallizers were carried out using special disposable thermocouples. According to the measurement results, the pulling speeds of the peripheral (extreme) streams were changed. For example, during casting of E76F rail steel, the metal temperature in the peripheral crystallizers was 1463-1470 ° С against 1464-1475 ° С in the central ones. The casting speed on the extreme streams was 0.51-0.60 m / min versus 0.50-0.55 m / min on the central streams.

The inventive method allowed

- increase the productivity of continuous casting by 1.4-7.0%;

- reduce the cost of continuously cast billets by an average of 0.74 rubles / t;

- reduce the number of rejected continuously cast billets on macrostructure defects by 0.012%.

Information sources

1. Auth. St. No. 458384, cl. B22D 11/14.

Claims (1)

The method of continuous casting of steel on a multi-strand radial machine for continuous casting of billets, including feeding liquid steel from a steel pouring ladle to an intermediate ladle and then through immersion nozzles into molds, forming continuously cast billets in molds, drawing them out of molds and cooling in the secondary cooling zone, characterized the fact that the drawing of the blanks from the peripheral molds is carried out at a speed higher than the drawing speed from the central molds by 0.01- 0.1 m / min depending on the temperature of the steel in the mold, and with a decrease in the temperature of the metal in the peripheral mold by 1 ° C compared with the central mold, the drawing speed from the peripheral mold is increased by 0.01 m / min.