SU1325088A1 - Method of treating steel outside a furnace - Google Patents

Abstract

The invention relates to methods of secondary treatment of steel and can be used for its desulfurization. UejTb of the invention - improving the mechanical properties of steel while reducing the consumption of aluminum and synthetic slag. The method includes pouring 33-40 kg / t into the bucket of synthetic slag, steel production into the ladle with the cut-off of converter slag, an additive of ferromanganese and silicomanganpa, blowing with silica-powder with a total flow rate of 1.6-3.5 kg / t, divided into two stages: before entering aluminum with an intensity of 30-90 kg / min to achieve oxygen activity of 0.001-0.015%, and after entering 0.8-2.5 kg / ton of aluminum with an intensity that is 1.3-2.0 times less than the original , for 4–10 minutes, entering with argon purge 0.1-g 0.5 kg / ton of carburizer. Steel has the following properties: OB 65 - 68 kg / mm; KCV., Jo 16-19 kgm / cm; p 9.2-10 kgm / cm; .10 fiber in the fracture. 1 hp f-ly, 1 tab. оо 1чЭ СП О 00 оо

Description

 , 13 The invention of services to metallurgy, in particular to methods for after-treatment of steel, and can be applied in the desulfurization of synthetically 1 day and calcium-containing

materials in the bucket.

The aim of the invention is to improve the mechanical properties of the steel while reducing the consumption of aluminum and synthetic slag.

Experiments have shown that it is advisable to pretreat a metal with silicocalcium.

after metal treatment, it is not synthetized quickly enough, and when combing slag is used, and silicon is introduced into manganese-containing deoxidizing agents. The absence of aluminum improves the desulfurizing ability of synthetic slag,

which decreases in the presence of aluminum material below O, 1 kg / ton of celemini due to its loss and the formation of Al O ,. . This reduces the aluminum consumption for smelting. With this method of processing steel, the consumption of synthetic slag is also reduced and total desulfurization increases due to the additional input of calcium oxides into synthetic slag.

It has been determined that silicocalcium purging should be carried out until oxygen activity values of 0.001-0.015% are achieved, which ensures minimum aluminum frenzy when it is introduced into the metal. The decrease in the activity of oxygen in the steel to values greater than 0.015% does not make it possible to smelt steel with a sulfur content of less than 0.006%, and a decrease in the activity of oxygen to a level of 0.001% is necessary in the production of steel with a sulfur content of not more than 0.004.

The introduction of aluminum in the amount of 0.8 to 2.5 kg / t provides effective conditions for the deep desulfuracin steel with a subsequent thin scale silicocalcium. The consumption of aluminum less than 0.8 kg / ton does not provide the required aluminum content in steel, and the consumption of CBbfflie 2.5 kg / ton does not cause a further decrease in the activity of oxygen.

When the metal is purged with silicocalcium for less than 4 min, the required degree of desulfurization is not achieved, and when it is purged for more than 10 min, considerable cooling of the metal occurs, which leads to a violation of the casting technology. If the intensity of silicocalcium purge decreases by more than 2 times, the duration of purge is 8

tally increases significantly, which leads to a noticeable cooling of the steel. A reduction in the intensity of the blowdown of less than 1.3 times leads to an increased aluminum carbon.

With a specific consumption of silicocalcium less than 1.6 kg / t, no modification of non-metallic inclusions is observed, and with a specific consumption of silicone, more than 3.5 kg / t, no further reduction of sulfur is observed.

When the silicocalcrate flow rate is less than 30 kg / min, the oxygen activity of the downflow sphipococalcium is greater than 90 kg / min. Metal splashes from the ladle are observed.

Reduced carbon consumption5

accordingly, since it does not allow the achievement of higher steel properties.

The increase in carbon-containing consumption of p (its material over 0.5 kg / t causes serious technological difficulties.

Steel is smelted in a 160 ton converter.

Before release into the steel pouring - 0 nts1 ladle is poured synthetic slag containing 50-56% CaO; 40-44%, the rest is impurities.

During the release, 16 kg / ton of ferromanganese and 5 kg / ton of silicomanganese are placed in the ladle. At the end of the release, the converter slag is cut off. Then the metal is blown with silicocalcium powder to the required amount of oxygen activity determined on the UKOS-1 device, after which aluminum is introduced into the ladle, then the metal is additionally purged with silicocalcium powder.

Before the introduction of aluminum, a sample is taken to determine the carbon content. According to the results of the analysis, after the metal was purged with silicoalkanium powder, carbon-containing material was introduced into the ladle.

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The metal is poured on the UNRS in the case with a section of 1550x240 mm. If one rolls onto a 17.5 mm thick sheet from which standard specimens are made, the test results are shown in the table.

Their analysis shows that the positive effect of O1 of the invention is to increase the quality of the metal by reducing the sulfur content to 0.003% and reducing the consumption of synthetic slag and aluminum.

Claims (2)

1. The method of after-treatment of steel, including the metal in the ladle, the cut-off of converter slag, the treatment with synthetic slag, the additive of aluminum in the amount of 0.8-2.5 kg / t and ferroalloys, the blowing of the metal with powdered materials and argon. 2. The method of pop. 1, which differs from the fact that, after purging with powdered silicocalcium, it differs in that In order to improve the mechanical properties, g tall is introduced when purging with argon O, 1 steel with a decrease in the consumption of aluminum 0.5 kg / t carburizer. Conjugation in the metal by release mas.X; carbon sulfur Consumption of synthetic slag, kg / t Sulfur content before purging, Z Oxygen activity in metal: before purging after the first purge Silikaltsi vegetable consumption, kg / t Purge intensity prior to entry aluminum, kg / min Aluminum consumption, kg / t Purge time after entering aluminum, NIN Purge intensity after entering aluminum, kg / min Amount of carburizer (graphite), kg / t Chemical content in finished steel, Mac.Z: and synthetic slag, metal purging with powdered silicocalcium is carried out with an intensity of 30-90 kg / min until the oxygen activity reaches 0.001-0.015%, then aluminum is introduced, after which the purge intensity is reduced 1.3-2 times and further blown through 4- 10 minutes with a total consumption of silicocalcium 1.6 - 3.5 kg / t. 2. The method of pop. 1, which differs from the fact that after purging with powdered silicocalcium in