SU969745A1 - Method for smelting steel - Google Patents

Description

The invention relates to ferrous metallurgy and can be used in steel-smelting workshops for smelting alloyed hoists.

There is a known method of melting nickel-alloyed steels, according to which its oxide 1 is used to reduce the consumption of metallic nickel.

The disadvantage of this method is the low absorption of nickel from powdered nitrous oxide, which is a result of its entrainment by furnace gases.

The closest in technical essence and the achieved result to the proposed is a method of steel melting, including alloying the melt with powdered nickel oxide in a gas jet 2.

The disadvantage of this method is the lack of parameters that allow one to obtain a given carbon content in the metal without additional operations — oxygen purging or carbonization. Additional operations lead to a decrease in the performance of the unit and an increase in the cost of steel.

The purpose of the invention is to reduce the cost of steel and intensify the steelmaking process.

The goal is achieved by the fact that according to the method of steelmaking, which includes doping the melt of a powder with nickel oxide in a gas stream, nickel oxide is introduced into the melt to a depth of 0.5-0.9 heights metal

10 baths with a carbon content determined by the formula

  bb-10- mnio

15

where the carbon content in the melt before the introduction of nitrous oxide,%;

 The required carbon content for this grade is.

20

- whether,%;

the mass of the injected nitrous by anyone

LH l, kg

To alloy the melt

to be used porhikoobrazna

25 oxide, containing 79-82% nickel.

When powdered nitrous is introduced into the cobalt melt in a gas jet, nickel particles must be reduced in the process of bubbling up of particles of nitrous.

Experiments have established that with the introduction of nitrous oxide to a depth of less than 0.5 of the height of the bath, some of the oxide does not have time to react and is carried away by furnace gases. With the introduction of nitrous oxide to a depth of more than 0.9 bath height, the lining is destroyed.

It has been established that with the introduction of 1 kg of nickel oxide to 1 t of melt, 66 10% of carbon is oxidized. Therefore, the moment the nickel oxide is introduced into the melt must be selected from the accounting for the carbon content of the current melting point and its final content. If this condition is not fulfilled, the carbon content may be less than the required one, or additional oxidation of carbon will be necessary.

An example. In a 120-ton open-hearth furnace fed by a scrap process, the melting of steel 20KhNZA Pors melted and like nickel oxide in the oxidation period of melting are introduced into

metal melt in a stream of nitrogen at different depths.

The technological parameters of the bottoms are given in the table.

The table shows that the absorption of nickel when entering nitrous oxide to a depth of 0.5 (melting 1.) and 0.9 (melting 3 and 4) of the bath height is 3.5–3.8% higher than to a depth of 0, 2 heights.

With a smaller carbon stock than is required from the resulting relationship (smelting 3), as a result of the introduction of nitrous oxide, the carbon content is obtained below the lower limit.

When the carbon content exceeds the required (smelting 4) and increased loss of nitrous oxide (smelting 2), additional oxidation of carbon is required by blowing the bath with oxygen.

The invention allows for the smelting of nickel-containing steel grades to achieve an economic effect of 9.76 rub. / Ton of steel.

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Claims (2)

B 79697 Claim method A method for smelting steel, including melt doping with porous nickel oxide in a gas stream, characterized in that 5 in order to reduce the cost of steel and intensify the process. Nickel oxide is introduced into the melt to a depth of 0.5-0.9 of the height of the metal bath with a carbon content of 10 determined by the formula f bb-Yum O58 where the carbon content in the melt before the introduction of nickel oxide,%; required carbon content for a given steel grade,%; - mass of injected nickel oxide, kg. Sources of information taken into account in the examination 1. Metallurgists of steel. Ed. IN AND. Yavoysky M., Metallurgists, 1973, p. 415. 2. Swedish patent W 406932, cl. C 21 C 7/00, 1979.