SU1553558A1 - Method of melting medium-carbon steel in open-hearth furnace - Google Patents

Abstract

This invention relates to the field of metallurgy. The purpose of the invention is to increase the toughness of steel and reduce the consumption of ferroalloys. The method consists in blowing the metal with argon with an intensity of 1.1-5 nm ³ / t ^. hours, starting with a carbon concentration of ± 0.03% of the top grade content for the steel produced, with an additive after 2-4 minutes into the aggregate of waste graphite production electrodes in an amount of 0.3-2 kg / ton of steel followed by metal release 6 - 10 minutes after the start of the purge into the ladle. 1 tab.

Description

The invention relates to metallurgy, more specifically to steelmaking.

The purpose of the invention is to increase the toughness of steel and reduce the consumption of ferroalloys.

The method is carried out as follows.

In the steel-smelting unit, the metal is refined and purged with argon, preliminary deoxidation and discharge of the metal into the ladle, followed by its final deoxidation; 1-5 nme / t-h, then after 2-4 minutes, waste from the graphitization of electrodes is set in the unit

(OPGE) in the amount of 0.3–2 kg / t of steel, 6–10 min after the start of the purge, metal is discharged into the ladle.

The essence of the method of steel smelting is that before the metal is released from the steelmaking unit, deep deoxidation is achieved, which increases the toughness of the steel and reduces the consumption of the melts by reducing the deoxidizing carbon.

Example. At the Nizhny Tagil Metallurgical Plant smelted on the proposed method, wheel steel 300 tons of the main open-hearth furnace. The smelting was carried out using a scrap metal process with a bath purging with oxygen through 2 submerged tuyeres. Furnace filling, charge heating, cast iron pouring, melting, slag descent,

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oxygen bathing, polishing and finishing of melting were carried out in accordance with the technological instruction TI 102-STM-16-81 on steel smelting in open-hearth furnaces and technological instruction, TI 102-STM-111-84 on melting and casting wheel and bandage steel.

During the preliminary deoxidation period, 2 inclined tuyeres were immersed in the metal, through which instead of oxygen, argon was supplied. In order to avoid arrest, argon was passed into the tuyeres before being immersed in the metal. In connection with a considerable overpressure in the working space of the furnace for the period of metal purging with argon, the valve of the middle batch window was half open. Instead of ferroalloys, OGPs from Chel Binsk Electrometallurgical Plant were attached to the furnace. According to VTT 139-13-84, they have the following characteristics on the OGGE: mass fraction of carbon 20- (60%, mass fraction of silicon carbide, particle size 0-40 mm , the mass fraction of lumps over 40 mm is 15%, the mass fraction of impurities (the battle of refractories, etc.) is 3%.

After the OGGE was added to the furnace, after a certain time, the metal was released into 2 ladles, where it was finally acidified.

Indicators of individual test heats characterizing the proposed method of steelmaking according to limiting parameters are listed in the table.

The results of the parameters presented in the table show that in the 1st and 5th heats using the proposed method of steel smelting and

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Exceeding the limits, the impact strength is at the level of the values for the steel of the base process, and the carbon in the finished steel corresponds to its lower and upper limit contents for the wheel steel.

The optimal parameters are heats 2-4, where the best final results are obtained in comparison with the base object.

The use of the proposed method of steel smelting provides, in comparison with the known steel, an increase in the steel toughness by 0.09-0.21 MJ / m2 and a reduction in consumption by an average of 3.37 kg / t of steel of 45% ferrosilicon and by 0.96 kg / t steel silicomanganese.

Claims (1)

Invention Formula The method of smelting medium carbon steel in an open-hearth furnace, including finishing, introducing carbon-containing material, purging the metal with argon, releasing into the ladle and final deoxidation in the ladle, characterized in of the material, use is made of the production of graphitization electrodes, the metal is blown with argon 6–10 minutes before being released at a carbon concentration of ± 0.03% of the upper grade limit, argon is fed at a rate of 1.1–5.0 n m3 / t-h., and production waste of graphitization of electrodes is introduced in the amount of 0.3-2.0 kg / ton of steel 2-4 minutes after the start of blowing. Steel wheel GOST 10791-81 contains, wt%: C 0.55-0.65; Mp 0.50-0.90; Si 0.20-0.42; Ryo.035; SS0.040. Purge duration in minutes. The deoxidizers in the furnace introduced the carbon content in the metal 0,57%. OPGE - waste production of graphitization electrodes. Alloy SKTiUA produced according to TU 14-5-130-80. The silicon content in the alloy is 43-50%.