SU1675340A1 - Method of melting rail steel in basic oxygen converter - Google Patents

Abstract

The invention relates to metallurgy, namely to the smelting of rail steel in oxygen converters. The purpose of the invention is to improve the quality of rail steel. Steel, ie, achieving low carbon content at 1630-1660 ° C, is released into a ladle with liquid iron with a temperature of 1300-1320 ° C and the filling stage is deactivated by 50-70% by volume of a complex silicon-calcium-zirconium aluminum alloy in the amount of 1.5-, 5 kg / t of steel. Using the method of curling steel to reduce the contamination of the head rails by 1.24-1.67 mm, /; Ennych by 0.51-P, OS mm and reduce the concentration of hydrogen 0.7 - 1.3 cm / 100 g. 1 gab

Description

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This invention relates to ferrous metallurgy, namely, the smelting of rail steel in an oxygen converter.

The purpose of the invention is to improve the quality of steel.

The method is carried out as follows.

The charge materials are loaded into a converter, then the melt is blown with oxygen to a low carbon content, steel with a temperature of 1630–16bO ° C is blown into a bucket with liquid iron at a cast iron temperature of 1300– 1320 ° C and the steel is deoxidized after filling the bucket with 50- 70% by volume of a complex silicon-calcium-zirconium-aluminum alloy in the amount of 1.5 kg / ton of steel of the following composition,%. 50-55 silicon 15-20 calcium;

6.7 zirconia; 3-4 aluminum; the rest of the iron

At elevated temperatures of steel and iron, silicon affinity for oxygen decreases and carbon affinity increases, resulting in low carbon steel which deoxidizes carbon in the iron to form gaseous deoxidation product (carbon monoxide), which is removed from the metal, resulting in steel not contaminated with oxide nmetallic inclusions. In addition, nitrogen and hydrogen are dissolved in the carbon monoxide bubbles that form, therefore, the gas saturation of rail steel is reduced.

Example. In a 250-tonne converter, 60 tons of scrap and 170 tons of iron are poured, and 16 tons of lime OOs XI are sown at the inlet of the purge.

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The flask is carried out with an oxygen consumption of 900 m 3 / min and is completed at a carbon content of 0.06% and a metal temperature of 1630-1660 ° C.

Low carbon steel is produced in a steel teeming ladle containing 30 tons of pig iron with a temperature of 1320 ° C. When filling a 70% by volume bucket, the metal is deoxidized with silicomanganese (2300 kg), ferromanganese (500 kg) and complex silicon-calcium-zirconium-aluminum alloy (500 kg).

Get rail steel of the following composition,%: carbon 0,74; manganese 0.9; silicon 0.28; sulfur 0.03; phosphorus 0.022. The yield of steel is 90%.

Technological parameters of pilot industrial melts. carried out on the proposed and known methods are shown in the table.

These experiments show that the least contamination of the rails with non-metallic inclusions and the hydrogen content in the finished steel is achieved by options 9-11. At the same time, in swimming trunks of the proposed method, compared with the known pollution of the head rails, decreases by 1.24-1.67 mm, bottom ones by 0.51-0.98 mm, and the hydrogen concentration is 0.7-1.3 cm3 / 100 g of steel .

Claims (1)

The invention method of smelting rail steel in an oxygen converter, including loading into the unit of charge materials, pouring iron, blowing oxygen to low carbon content, the release of the melt with a temperature of 1630-1660 ° C in a ladle with liquid cast iron and the introduction of deoxidizing agents for filling the ladle, characterized in that, in order to improve the quality, the complex silicon-calcium-zirconium-aluminum alloy is additionally introduced into the melt the amount of 1.5-2.5 kg / ton of steel, while the alloy is introduced after filling the bucket at 50-70% by volume. and the temperature of the iron in the ladle is 1300-1320 ° C.