SU535354A1 - The method of steelmaking - Google Patents

Description

Thus, to obtain the required height of the molten metal, it is necessary to rotate the furnace, each according to the timing of operation of the EAF-200 furnaces, with a duration of 3-5 minutes. Therefore, this method of steelmaking leads to a decrease in furnace productivity.

The aim of the invention is to increase the productivity of the furnace. To do this, according to the proposed method, including charging of the charge, penetration of wells and addition of the charge, during the filling period at a level of 0.20-0.40 of the height of the charge, an insulating layer 0, 20 in thickness from the height of the charge is laid, consisting of materials with low thermal conductivity , for example, iron-containing compounds such as pellets or slag-forming materials, or mixtures of these substances.

Electrodes, melting the mixture to an insulating layer (LAYER), slow down the downward movement due to the low thermal conductivity of the insulating layer. For the same reason, most of the arc energy is absorbed by the overlying charge materials, which leads to an increase in the diameter of the wells and the amount of molten metal.

Thus, the layer of liquid metal on the furnace hearth is sufficient to maintain stable arc burning and eliminates the possibility of damage to the furnace lining.

The thickness of the insulating layer depends on the thermophysical properties of the materials of the layer and is within 0.05-0.20 of the height of the charge. For example, when loading lime in the amount of 3% of seca charge, the thickness of the insulating layer is 20 cm or 0.07 of the height of the charge.

The drawing shows an arc steel-smelting furnace during the period of the melting of wells, a section.

Charged in furnace 1 contains an insulating layer 2, consisting, for example, of iron-containing compounds such as pellets or slag-forming materials, or mixtures of these substances. Due to the low thermal conductivity of the insulating layer, the movement of the electrodes 3 slows down, an increase in the volume of wells 4 and the amount of molten metal occurs.

To calculate the height of the molten metal, k-1.22 m is taken — the diameter of the well above the insulating layer is equal to two diameters of the electrode. The insulating layer is located at a height of 0.25 charge. According to the formula

Tsh

l (D,) - 0.75- / i + DiX

UZH.Y - is

4 T

(3)

X 0,25Я

get UZH.M -2,23 m from where by the formula (1) are found // 225 m. Such a layer of liquid metal is sufficient to maintain a stable burning of electric arcs. A specific calculation example is given for

a layer of lime up to 20 cm thick or 0.07 from the HEIGHT of the charge.

Using this method of steelmaking, in comparison with the known method, the melting time is reduced by 10-

15 minutes, which allows to increase the productivity of the furnace by 2.8-4.2%.

Claims (4)

1. A method of steel smelting, including filling the charge in an electric arc furnace, penetration of wells and melting, characterized in that, in order to increase furnace productivity, during the filling period at a level of 40, the height of the charge is laid a layer of materials with low thermal conductivity , 0.05-0.20 in thickness from the height of the stitch 2. A method according to claim 1, characterized in that iron-containing compounds of the type of pellets are used as a material having a low thermal conductivity. 3. A method according to claim 1, characterized in that slag-forming materials are used as a material having a low thermal conductivity. 4. A method according to claim 1, characterized in that as a material having a low thermal conductivity, a mixture of iron-containing compounds such as pellets and slag-forming materials is used. The source of information taken into account in the examination: 55 1. N. Kh. Okorokov. “Arc steel-smelting furnaces, M., 1971, p. 253.