SU992592A1 - Method for smelting steel in acid open-hearth furnaces - Google Patents

Description

The invention relates to ferrous metallurgy, namely, steel production in open-hearth furnaces.

There is a known method of steel smelting in open-hearth furnaces, including filling of metal charge and slag-forming / smelting and deoxidation of slag 520 minutes before the release of ferrosilicon production waste in the amount of 315 kg / t Cl steel.

The disadvantage of this method is its low productivity due to the fact that the process of silicon reduction takes place under conditions of low slag oxidation and high viscosity, which leads to an increase in the duration of smelting finishing.

The closest to the present invention is a method of steel smelting in open-hearth furnaces, including the filling of metal charge and slag-forming, melting, refinement and deoxidation, and 10-20 kg / ton of steel production waste is deposited 10-20 minutes before being released to the furnace 5-15 minutes before the release of 410 kg / t of alumina silicon steel 2 3.

The disadvantages of this method are the long duration of the process and the high consumption of ferromanganese for steel deoxidation.

The purpose of the Invention is to intensify the process of silicon recovery.

The goal was achieved by the fact that during steel smelting in sour open-hearth furnaces, including the filling of megalloshchits and slag-forming, melting, finishing and deoxidation, during

10 finishing on powdered silicon carbide is placed on the slag.

Powdered silicon carbide prisubit when the temperature of the metal 1BZO-1bBO C and content

15 carbon in the metashe is 0.25-0.30% above the upper limit for this steel grade.

Silicon carbide additives are made in 3-4 portions with an interval of 15-20 minutes.

20 with its total consumption of 2.0-2.5 kg / t.

The consumption of ferromanganese, privalivaemogo along the dovodi, reduced to 1.5-2.5 kg / t.

Silicon carbide, reacting with the components of the upper slag layer, reduces its oxidation and at the same time increases the silica content in it. This reduces the oxidative effects of the furnace atmosphere and creates

Claims (4)

30, on the one hand, favorable cream for fast recovery of the cream in the second half of the finishing, and on the other hand, it prevents the oxidation of manganese, which makes it possible (to reduce its consumption. With a consumption of ferromanganese more than 2.5 kg / t, there is a decrease speedy oxidation of carbon due to deacidification of the bath. With the introduction of ferromanganese in an amount of less than 1.5 kg / t, the rate of silicon reduction decreases, as manganese to a certain extent contributes to its reduction. When the bath temperature is below 1630 ° C When silicon is consumed, and at a temperature above leeo-c, the wear of the furnace lining increases.When silicon carbide consumption is less than 2.0 kg / ton, the silicon recovery rate decreases, while m consumption exceeds 2.5 kg / an excessive thickening of the slag occurs and, as a result, a decrease in the rate of carbon oxidation. The simultaneous introduction of the entire calculated amount of silicon carbide leads to a strong deoxidation of slag and a sharp decrease in the rate of carbon oxidation. Therefore, silicon carbide is set in 3-4 portions with an interval of 15-2Q minutes. This method of its input provides a high rate of oxidation of carbon and an abnormal increase in the concentration of silicon in the bath. At concentrations of carbon in excess of 0.25-0.30% above the specified upper limit for the downhole steel grade before deoxidation, there are cases when the bath has a temperature below, and at lower temperatures there is a danger of incomplete recovery of silicon, i.e. to a concentration less than 0/17%. Example 1. In an acidic open-hearth furnace, a charge of 100 tons is filled up with 90 tons of scrap, 15 tons of pig iron, 0.3 tons of nickel, 5 tons of recycled slag and 0.5 chamotte. After the charge is melted, 400 kg of iron ore is applied to accelerate the oxidation of carbon s baths. When the temperature of the metal and the carbon content in the bath is 0.58%, which is 0.29% higher than the carbon content before deoxidation, the first portion of the silicon carbide powder is set down. After 10 minutes, 225 kg of ferromanganese is deposited, which is 2.25 kg / ton. The next batch of silicon carbide is set at 10 minutes after the addition of ferromanganese. Afterwards, two portions of carbide and silicon are seated after 1520 minutes so that their total consumption is 2.0-2.5 kg / t, after reaching the metal temperature of 1670 ° C and the carbon content of 0.29%, melting is reduced to 400 kg of ferromanganese and 1.5 tons of ferrochrome and after 40 min produce. The content of reduced silicon in the metal is 0.25%. Duration, melting will be 11 hours and 20 minutes. Example 2. In an acidic open-hearth furnace with a cage of 100 tons, 92 tons of scrap, 15 tons of pig iron, 0.3 tons of nickel, 5.5 tons of recycled slag and 0, 5 tons of chamotte are poured. After the charge is melted, 350 kg of iron ore are placed in a bath. When the metal temperature reaches 1b35 ° C and the carbon content in the bath is 0.55%, which is 0.26% higher than the carbon content before deoxidation, the first batch of silicon carbide is seated. After 5 minutes, 200 kg of ferromanganese is applied, which is 2, .0 kg / ton. Subsequent Tpii portions of silicon carbide are seated at an interval of 15 minutes at a total flow rate of 2.1 kg / ton. After the temperature of the metal reached 1660 ° C and the carbon content of 0.29%, the melting is dried, the seating of 440 kg of ferromanganese and 1.4 tons of ferrochrome is released after 45 minutes. The content of reduced silicon in the metal is 0.22%. Duration i melting will be .11 h 05 min. Example 3 Melting is carried out using conventional technology. In a sour open-hearth furnace, with a cage of 100 tons, 90 tons of scrap, 16 tons of pig iron, 0.3 tons of nickel, 5 tons of recycled slag and 0.5 tons of chamotte are piled up. 30 minutes after the charge is melted, 300 kg of ferromanganese are sown, then after 30 minutes 400 kg of iron ore are introduced. After 40 minutes, another 250 kg of ferromanganese are added. After reaching the temperature of the metal jH560 c and the carbon content of 0.28%, the melting is deacidified, the injection of 550 kg of silico-manganese, 8 tons of ferrochrome, and after 40 minutes is released. The content of reduced silicon in the meta-scale before deoxidation is 0.16%. The duration of melting will be 12 hours 00 minutes. The use of the proposed method of steel smelting in an acidic open-hearth furnace provides an accelerated recovery of silicon in the second half of the adjustment to a concentration of 0.170, 37%, which will reduce the duration of melting by 0.5-1.0 hours, reducing the consumption of ferromanganese, while planting in the furnace during the finishing from 5.5-6.0 kg / t to 1.5-2.5 kg / t. The economic effect of using the proposed method will be .2.13 rubles / ton of steel. Claim 1, A method of steel smelting in acidic open-hearth furnaces, including the filling of metal chaff and slag-forming, melting, refining and deoxidation, characterized in that, in order to intensify the process of restoring silicon, in the period of refining on the donkey, it is powdered. silicon carbide. 2, the way pop; 1, characterized in that the powdered silicon carbide is seated when the temperature of the metal 1630-1 bbOs is reached; the carbon content in the metal is 0.25-0.30% higher than the upper limit for this steel grade, 3. Spobbb on PP. 1 and 2, 6 t of that, silicon carbide additives are produced in 3-4 portions with an interval of 15-20 minutes with a total flow rate of 2.0-2.5. 4. Method according to paragraphs. 1-3, characterized in that the consumption of ferromanganese, prisazhivaemaya during finishing, is reduced to 1.5-2.5 kg / ton. Sources of information taken into account in the examination 1. USSR author's certificate About 551372, cl. C 21 C 5/04, 1977. 2. Authors certificate of the USSR 859460, cl. C 21 C 5/04, 1981.