SU1071645A1 - Method for making steel - Google Patents

Description

O5 4 SP The invention relates to ferrous metallurgy, and more specifically to methods for smelting steel in arc steelmaking furnaces. The method of steel production in an arc furnace is known, which includes the following series of operations: melting the charge, renewing the melting slag with lime and solid oxidizer additives (iron ore, sinter, iron ore, etc.) oxygen blowing of the metal, fractional oxidation pressure, introduction bath of lumpy alloying materials, slag-forming additive, / deoxidation of the refining slag with powdered deoxidizing agents and the release of metal and slag into the ladle til. The disadvantages of the method are low rates of lime dissolution in the oxidized slow-moving Low active), which leads to a long period of lime dissolution (when entering 30 kg / ton of lime into the 100-ton furnace, its dissolution in the oxidizing slag is 57 MIN) and, therefore, to prolong the refining period; high amounts of powdered deoxidizers due to their introduction on the surface of the bath for 30-35 minutes before the metal is released from the furnace when the arcs are working; high carbonization of alloying elements, both due to the absence of preliminary deoxidation of the bath-aluminum and due to early (at the beginning of refining; metal doping for a complete chemical analysis; impossibility of ensuring low sulfur content in steel due to oxidation of powdered deoxidizers in the process of holding the metal under arcs in the kiln and the thickening of the donkey caused by the increase in the Mgp content in the slag of the kiln lining. The indicated reasons lead to the need to spend a long refining period of smelting and, constituting, as a rule, 50-, 80 minutes. The closest to the technical essence and the achieved result is a method of steel smelting in an arc furnace, including melting the charge, updating the melting slag with lime and oxidant additives, blowing metal with oxygen, partially removing the oxidizing slag, alloying of metal, the addition of slag-forming agents, deoxidation of the refined slag, and the release of metal and slag into the ladle. The method is carried out as follows: load and melt this mixture, inject lime and. the iron ore is blown through with oxygen through a lance, the oxidizing ass is partially pumped, alloyed ferroalloys are added to, refining slag is induced by lime, diffusion of slag is produced, and then the metal is released into the ladle C2.1. A disadvantage of the known technology is the low dissolution rates of slag-forming, which leads to a lengthening of the metal refining period, low, the rate of exchange reactions of the carburizer (as well as powder, a deoxidizing agent; iron oxide, which takes a long time to reduce iron from slag oxides, as well as high waste of deoxidizers with a long exposure of the metal in the furnace for its refining. with powerful electric furnace arcs. The aim of the invention is to reduce the time of refining, reducing the The goal is achieved by the fact that, according to the method of steel production, including melting, charge, renewing the melting spike with lime and oxidant additives, purging the metal with oxygen, partially removing oxidizing slag, alloying the metal, adding slag-forming materials , the deoxidation of the refined slag slag and the release of metal and slag into the residue of the oxidizer | slag is introduced into the carburizer in the amount of 0.8-2.7 kg / t together. with lime in the amount of 18-30 kg / t and thinning slag in the amount of 1.5-4.0 kg / t, alloying the metal simultaneously with the deoxidation of slag with aluminum in the amount of 0.5-1.2 kg / t, and for 1- 4 minutes before the metal is turned off, the furnace is turned off and at the same time, on the bath surface, vvrd, kg / t: silico. Lysar 1.1 - 2.8; aluminum 0.72, 0 / powder eu3–3–3, thinner slag 2–4, 5 followed by mixing the bath. Coke, stone or lignite, petroleum pitch, graphite and other carbon-based materials can be used as a carburizer, and chamotte, bauxite, fluorspar and other natural or synthetic materials with the ability to liquefy steelmaking slags can be used as slag thinner. The method of removing part of the oxidizing slag from the furnace after the oxidation of impurities with oxygen is widely known and allows for a reduction in the metal's re-phosphorization. last leading de-scoop. The addition of slag-forming and alloying of the metal makes it possible to reduce

the activity of ferrous oxide of slag, both by diluting the slag with lime and fluorspar, and by reducing the iron of the slug by the carburizer for these, together with the introduction of slag-forming and carburizer. The introduction of lime together with the dilution of slag, such as bauxite, makes it possible to have an active high-viscous slag in the initial period of the metal refining, and the addition of the carburizer, on the one hand, reduces the time of lime dissolution in the oxidative slag from 7 8 TO 1 - 2 min, and, on the other hand, before metal alloying, 15, low concentrations of iron oxides in the slag (less than 10%).

An additive to lime less than 1.5 kg / ton of thinner slag does not allow for the production of liquid mobile slag, and the addition of 20.0 kg / ton of thinner ensures the fluidity of even magnesia shpak (Cs magnesia content of about 18-22%).

The addition of lime to less than 0.8 kg / t 25 of the carburizer does not allow reducing the concentration of the amount of iron oxides in the slag to less than 10%, and the addition of more

2.7 kg / t carburizer leads to metal carbonization. Jq

Combining the preliminary deoxidation of slag with aluminum with alloying of the metal allows stabilizing the absorption of steel alloying by reducing the oxygen, / and yes content in the slag in the doping zone, while combining these operations reduces the refining time by; 3-5 minutes without compromising the quality of the steel .

At the same time, the subsequent introduction of silicocalcium into 0 metal causes an incomplete alloying of the metal with silicon (alloying with allowance for silicon introduced by silicocalcium),

The introduction into the slag together with the alloying less than 0.5 kg / ton of aluminum does not prevent the alloying from the slag from oxidation, since

iron oxides in slag does not decrease

lu%, and the introduction of more than 1.2 kg / t 50 aluminum in the slag do not lead: t to obtain an additional positive effect ...

Simultaneous administration, per minute

before the release of powder5. Ferrosium. 55 slags for slag deoxidation, gshyumi-ni, silicocalcium and slag thinner with the furnace switched off; allows you to completely eliminate waste items in the slag and metal due to the long-60-ti refining period and work at this time of electric arcs,

The simultaneous introduction of powdered deoxidizers in the slag and lump materials in the metal. So-called

It doesn’t allow operations and thus shortens the refining period, eliminates waste of powdered and lumpy materials by eliminating the influence of the arc and reducing the exposure time in the furnace for 1.4 minutes. There is not enough time for 1 minute to give materials and their mixing, and the time spent by the furnace bath for 4 minutes without the influence of arcs leads to a loss of metal temperature and. the need to turn on the stove.

The lower limit for introducing a silicocalcium into the metal, equal to 1.1 kg / t, is due to the need to obtain op. the maximum degree of desulfurization of the metal, and the introduction of more than 2.8 kg / t of silicocalcium is not justified exonadically. The introduction of aluminum is advisable to produce 50% powder, and 50% a piece for the deoxidation of slag and me-. tally, respectively. Dacha less than 0.7 kg / ton of aluminum does not result in the deoxidation of slag and metal required to obtain a sulfur content in the metal of less than 0.020%, and the introduction of more than 2 kg / ton of aluminum leads to a tightening of the channel bucket. The limits for the introduction of powdered ferrosilicon into slag kg / t are due to the smelting of steel for various purposes, with the high consumption values attributable to low carbon steel and m, and lower to high carbon and alloyed.

The introduction of less than 2 kg / ton of diluent into the slag does not allow for the production of liquid mobile slag, and the introduction of more than 4.5 kg / ton of thinner does not lead to a further increase in the fluidity of the slag.

. EXAMPLE 1. In a 100-ton arc furnace, smelting St 20, the charge was melted, the smelting slag was renewed with descent and additives of 20 kg / t of lime and 100 kg / t of iron ore pellets, the metal was blown with oxygen at a rate of 2pOO, removed 50% of oxidizing slag, which corresponds to the remaining 3 slag in the furnace, a mixture of 1800 kg (18 kg / ton), coke 80 kg (0.8 kg / ton) and bauxite 150 kg {1.5 kg / t), alloyed the steel with silicon to obtain it in the metal of 0.15% and manganese for a complete chemical analysis by introducing the forces1 of co-manganese into the metal simultaneously with the introduction of 50 kg fO, 5 kg / ton. with aluminum into slag, the metal was heated to the temperature of release, 4 minutes before the release, the furnace was turned off, the electrodes were lifted, 110 kg (-1.1 kg / t) were introduced at the same time, silicocalcium, 70 kg (0.7 kg / t). kg of powder and 35 kg of lump aluminum aluminum., 100 kg XI kg / t) of ferrosilicon powder, 200 kg (2 kg / t)) of fluorspar / stirred bath and, without turning on the furnace, released metal and slag into the casting ladle.

The time of metal refining in the furnace is reduced by 18 minutes (as compared with the known Method), the supply of materials to the furnace by hand with flops is completely eliminated, the sulfur content is reduced by 0.010 abs.%, And the through absorption of silicon is increased by 17%.

EXAMPLE 2. In a 50-ton furnace, when smelting steel 25G2S, after deoxidation of the charge, slag was updated by downloading, lime additives 15 kg / t and rolling scale 10 fcr / t, the metal was blown with oxygen at a rate of 1800 m / h, 30% of the slag was removed, leaving it in the furnace in an amount of 4 tons. A mixture consisting of i- was introduced into the residue of the oxidizing slag. Conduct in the amount of 1200 kg (24 kg / t) of coal coal 87.5 kg. (17.5 kg / t) Fluorite concentrate 137.5 kg (2.75 kg / t). The metal was doped with silicon to obtain it in a metal of 0.20% and with manganese with the simultaneous introduction of 42.5 kg (0.85 kg / ton) of aluminum into the slag. 2.5 minutes before production, at the temperature of the metal, the furnace was turned off, the electrodes were lifted, while 97.5 kg of silicocalcium tl, 95 kg / t, 67.5 (1.35 kg / t) of aluminum (33.75 kg of powder and 33.75 lump alc 4ini), 100 kg (2 kg / ton) of ferrosilicon powder and 162.5 kg (3.25 kg / ton) of fluorspar. After mixing the bath, the metal and slag were released from the furnace.

The time of the refining period is reduced by 17 minutes, the supply of materials to the furnace by hand is completely excluded, the sulfur content is reduced by 0.01020 abs.%, And the through digestion of fertilizer is increased by 11%.

Example 3. When smelting 4OX steel in a 10-ton furnace, the charge was melted, slag was updated with lime and iron ore additives, oxygen was blown through the metal at 4OX and 10% of oxidizing slag was removed, leaving 500 kg for the remainder of the slag. a mixture of 300 kg of lime (30 kg / tU, pitch coke 27 kg 2.7 kg / t) and bauxite 40 kg (4. O kg / t), was introduced into the metal ferrochrome and ferrosilicon at 0.15% of its content, and in the slag - 12 kg (1.2 kg / t) of lump aluminum, the metal was heated to, the furnace was turned off, the electrodes were lifted, the baths were given to the surface at the same time ( with one mulberry V 28 kg silicocalcium (2.8 kg / t), 20 kg (kg / t) aluminum w (10 kg of powder and 10 kg of a piece, 30 kg (3 kg / t) of ferrosilicon powder and 45 kg (4.5 kg / t) of fireclay. After mixing the bath, the metal and slag were released into the casting ladle.

The time of the refining period is shortened by 11 missions, the supply of materials to the furnace by hand is completely excluded, the sulfur content of sulfur stones is 0.009 abs.%, And the through absorption of silicon increases by 15%.

The use of the proposed method of steel production in Uzbekmetzavod ESC, allows you to completely refuse to give powdered deoxidizing agents to slag with shovels, reduce the duration of the refining period by 12 minutes (on average), reduce the sulfur content in the finished metal and accordingly the number of breakthroughs of the metal when casting to the UNPRS increase the absorption silicon by 15%. The GBD economic effect of use is 1.4-1.6 rubles / ton, depending on the steel grade.

Claims (4)

> STEEL MANUFACTURING _METHOD,; including melting the charge, updating the slag by melting with lime and oxidizing agents, purging the metal with oxygen, partially removing oxidizing slag, alloying the metal, adding slag-forming additives, deoxidizing the refining slag, and releasing metal and slag into the ladle, I mean that, in order to reduce the refining time, reduce the sulfur content in the finished metal and increase the degree of assimilation of silicon, a carburizer is introduced in the amount of 0.8- 2.7 kg / t, together with lime in an amount of 18-30 kg / t and a slag thinner in an amount of 1.5-4.0 kg / t, alloy the metal simultaneously with the oxidation of the slag with aluminum in an amount of .0.5 1.2 kg / t, and 1-4 minutes before the metal is released, the furnace is turned off and at the same time it is introduced onto the bath surface, kg / t: silicocalcium 1.1-2.8) aluminum 0.7-2.0) ferrosilicon powder 1.0- 3.0) shpak thinner 2.0- 4.5 followed by stirring the bath. ‘