SU532634A1 - Steel Production Method - Google Patents

Description

; 54) METHOD OF MANUFACTURING STEEL IN ARC FURNACES

one

This invention relates to the field of ferrous metallurgy; and it had a way to produce steel in arc furnaces.

There is a known method of steel smelting, which includes a mill and melting of the charge, induction of lime-ferrous slag with its download at the end of the oxidation period, directing lime slag with lime and chamotte doping, doping, and lime powder at the end of the period before release, downloading of the lime slag completely before the release, as well as release of the metal into the ladle with a synthetic reduction of the refining slag, deoxidation of the areoMtffiHOM B after the release and pouring of the slag.

This method is distinguished by double-bed ska-shba of sh.chak, a ladle consumption of ferroalloys due to additionally oxidized during the period of finishing and deficiency, and high value of raw materials for the preparation of synthetic sh.laka. In addition, the section for the non-direct removal of slag from the make-up period before the release of smelting in the rounds,

for example, 2OO-ton arc furnaces, it gets into the ladle and the physicochemical properties of the squeezed lime-alumina slag deteriorate, hence the quality of the steel produced is reduced.

There is also known a method of steel smelting which includes charging and melting the charge, induction of oxidative lime-iron slag, complete download at the end of the oxidation period, alloying, deoxidation of metal with lump aluminum, induction of lime slag by addition of a mixture of lime, fluorspar and chamotte, set before the current; slag coke, then a mixture of lime, ferrosilicon and ground coke, set in a ratio of 6: 3: 1 with a metal aging under deoxidized slag and metal deoxidation nna lump aluminum 3-5 microns. before the release in the amount of 0.04-0.06%, the release of melting in the ladle and casting f2j.

However, the recovery period lasts up to 2 hours of 30 minutes, the ci-pumping operations of the oxidizing sp; 1kA and supporting a high reduction of the reduction weight-loss are long. The combination of the depth of 1H1SH metal deoxidation in lumpy metal with diffusion. The exposure of its iodine to reducing slag leads to the deterioration of steel quality, because during the production of highly deoxidized metal, secondary oxidation develops. To carry out effectively the deep deoxidation of the metal by manually inserting the stirrups on the rods and keeping the slag in a deoxidized state during the entire reduction period (1 hour 30 minutes - 2 hours 30 minutes) neo-impurity IiO in large 200-ton electric furnaces. Melting bearing steel by known technology due to the long duration of the recovery period, along with a change in furnace performance, reduces the durability of the lining of the arc furnace, increases the duration of furnace filling operations after production, increasing the consumption of filling materials. Erosis of the bottom during this period contaminates steel with nonmetallic inclusions, thereby increasing its quality. The purpose of the invention is to improve the quality of steel and furnace productivity. This is achieved by the fact that the slag-forming additive during the recovery period is carried out on a specially left basis. In an amount of 1-3% of the weight of the sludge, the slag of the oxidation period; The chamotte of the smelting spar and lime is added to the portions, set with a shank of 1 to 4 ms, with the furnace turned on, into the zone of burning electric arcs. Additive to slag powder - deoxidizers of coke, ferrosilicon, fluorspar and aluminum is carried out for 5-30 M1Sh before the release of smelting in the amount of 20-70% of the mass of prissed lime at a ratio of {1-3) :( 1.6-5 ) :( O, 3-2), respectively, with a throwing machine, the scattering angle 1 and the jet 30-60, and the additive in the bucket aluminum and fluorspar is carried out in an amount of 5-40% by weight of the impregnated lime at the ratio (1 -3): () respectively. Additive of shamata, fluorspar and lime: ka ready slag melt in portions to the zone of electric arcs facilitating the rapid dissolution of slag-forming avenues. The addition of deoxidizing powders prior to release eliminates the need for a time-consuming operation to maintain strong slag deoxidation throughout the recovery period, maintains optimal oxidation at 100 ui before release (0.005 - 0.008%), reduces the amount of converted magnesium oxide in slag; to promote the tech; the most active refining slag in the processing of steel in the ladle. Machine addition, the opening angle of koPI-S torahs 30–60, at the indicated ratio of powders, contributes to the extremely rapid formation of active lavish slag. Additive in KOBUI al l1N1SH and fluorspar in the amount of 4-40% of the weight of the precipitated lime in fires (1-3):. (- - 3); The slag, which is brought to the final form, with the required HHpjTomniViii of S5I, increases the amount of reduced calcium from the slag, which is 3c; Te; v ;, dissolving in the fatigue J spacke, dramatically increases its refining ability, modifies the ingot structure and the resulting nonmetallic inclusions of oxides, contributes to the equilibrium of the number of crystallized steel. In order to increase the dissolved calcium content in the slag and increase the shredding slag metal to metal and non-metal; 1 and the final formation of the slag composition in the ladle is carried out on the metal and (before releases) of the metal) a.-1S; incl. fluorspar and silicocalcium in coarse (): (. oshki and respectively. This combination of technological methods allows, regardless of the capacity of the arc furnace, to obtain active reducing refined slag in the ladle, which metal processing during production in combination with simultaneous deoxidation of aluminum mixed with spar causes an increase in the purity of steel by nonmetallic inclusions of all kinds, contributes to ensuring the durability of products made of metal, for example, in an electric steel furnace, for example A 200-tonne ere is charged with 500OO kg of pig iron, 15000 kg of carbon steel waste and melted at the maximum transformer capacity with lime additives from iron ore. In the process of melting the charge and during the boiling time of the metal, the oxidizing slag is periodically updated. phosphorus not more than 0; 015%, carbon not less than 0.85% and