SU697570A1 - Method of producing synthetic cast iron - Google Patents

Description

(54) METHOD OF OBTAINING SYNTHETIC PIG IRON

one

The invention relates to metallurgy and can be used in the foundry industry.

A known method of producing iron and steel and metal waste by duplex processes, which means that the charge of ferroalloys and carburizers charge in the electric arc furnace is loaded simultaneously, and after the metal is melted and overheated to 1550-1600 ° C, it is fused and corrected chemical composition with the addition of ferroalloy and carburizers on the metal mirror 1.

The disadvantage of this method is the high waste of the carburizer (up to 30-35%) and ferroalloys (up to 79%) when they are melted in an arc furnace. This is due to the fact that, when operating on a solid charge, the carburizer is slagged by the oxides formed and burns due to high temperatures in the electrode area. The high-iron slag formed during the melting of the charge oxidizes and legiruates the elements that are loaded into the grinder.

The closest in technical essence and the achieved effect to the invention is a method of remelting scrap and its alloying in an electric arc furnace and finishing on carbon in an induction electric furnace. Melting LSG1a and its doping is carried out in an arc furnace and provides for the preparation in the melt of not

0 above 0.03% of carbon, as well as the removal of aluminum, silicon, and titanium from metal by introducing special deoxidizing agents into the melt. Increasing the carbon content in the metal to

5, the required concentration is produced in a vacuum induction furnace 2.

This method does not eliminate stupor.

0 alloying elements. The low concentration of carbon in the melt contributes to the oxidation of elements and an increase in irrecoverable metal losses (up to 10-15%). The finishing of metal at the angle to the type in an induction vacuum furnace requires additional time and energy consumption.

The aim of the invention is to develop a method for smelting synthetic cast iron from metal scrap, allowing

reduce carbon waste and ferroalloys, reduce energy consumption, increase process productivity.

The goal is achieved by the fact that on the remainder of the melt of the previous melt, firstly, the hydrogen-containing materials are loaded in the amount of 60-70% of their total amount and after the molten metal charge is melted, the metal is heated to a temperature of 14 ° C to 1470 ° C to the bottom of the transfer ladle before the metal is drained from the furnace into it, and ferroalloys are loaded to the bottom of the induction electric furnace before the metal is transferred from the transfer bucket to it.

Download carbon-containing material in the amount of 60-. 70% of the total weight of the remainder of the liquid;., The metal of the previous melting contributes to a more rapid absorption of carbon-containing material and reduce its carbon loss. This also contributes to the overheating of the metal to a temperature of 1460-1470 C. |

Loading the remaining part of the carbon-containing material to the bottom of the ladle also reduces carbon frenzy, because the degree of its assimilation in ii-lvshee when metal is drained is much more significant than in an arc furnace.

Entering ferroalloys at the bottom of an induction furnace before metal is drained into it facilitates their rapid and complete assimilation. The waste of the elements is practically eliminated, which is associated with the absence of oxidizing slags and the rapid assimilation of ferroalloys under the conditions of intensive mixing of the metal when it is drained into the furnace.

The implementation,; of the above operations reduces energy consumption, shortens the melting time and increases the productivity of the process as a whole.

Increasing the amount of carbon-containing material loaded into the arc furnace above the recommended limits leads to an increase in the energy consumption for its dissolution, requires more time for the carburizing process. This is due to the fact that the dissolution of carbon is of a diffusion nature, therefore, the greater the weight of carbon loaded, the longer the process of its assimilation.

Increasing the melting time leads to increased power consumption.

Reducing the amount of carbon-containing material that is loaded into the arc furnace below recommended limits is impractical because the proportion of carbon-containing material that is loaded into the ladle increases. An increase in the amount of feed to the carburettor leads to a decrease in its absorption and an excessive drop in the temperature of the metal in the ladle.

Overheating of the metal in the arc furnace above the specified temperature range leads to an increase in carbon loss and an increase in power consumption and requires more time for the process. Overheating of the metal below the proposed temperatures reduces the degree of absorption of the carburizer in the ladle.

Synthetic cast iron was smelted from metal waste duplex-process: electric arc furnace DSP-25 electric arc furnace of industrial frequency IChT-10. The chemical composition of the pig iron is as follows, wt.%: C 3.54; Si 1.8; Mp 0.62; S 0.03; P 0.04; Cr 2.1; N1 1.5.

The angle of the holding material in the nida of crushed graphite in the amount of 60% of its calculated weight for smelting and steel metal waste is loaded into the arc furnace on the mirror remaining from the previous smelting of metal.

The remainder of the liquid metal, based on the total weight of the previous melt, is 20%. After the metal charge is melted, the melt is overheated to 1460 ° C.

After overheating, the metal from the furnace is poured into a transfer ladle, at the bottom of which the remaining part (4%) of crushed graphite, FS-18 ferrosilicon, FC F650 ferrochromium, is put. .

Melting is also carried out with loading into the arc furnace of metal charge and ferroalloys, and crushed graphite into an induction furnace according to a known method.

The results of the bottoms are tabulated.

Single loading into the arc furnace of metal charge, ferroalloys and carbon-containing materials according to a known method 1.

Downloading the components of the charge by the known method 2. Loading components

Claims (2)

Charges according to the proposed method. The use of the method of smelting synthetic iron with the use of arc and induction electric furnaces provides the following advantages in comparison with the existing methods: it reduces carbon loss by 5–15% and. practically eliminates waste of ferroalloys; reduces energy consumption by 20-35%; reduces the time required for melting by 35-55% and, accordingly, increases the productivity of the process; reduces the overall cost of producing molded products. Claims of Invention A method for producing synthetic cast iron, comprising loading into the filling of metal charge and carbon-containing materials, melting them in an electric arc furnace, and releasing metal into a ladle. 72130 10 7 15 5 910201510 15b 59515 0.1 20.1 overflowing into the induction furnace and doping it in it, which is different, to reduce carbon loss and ferroalloys, reduce power consumption, increase process productivity, before loading the charge, the melt of the precursor melt is loaded 60-70% of carbon-containing materials of the total number of them, overheat the charge to a temperature of 1460-1470 0; The remaining carbonaceous material is introduced into the bottom of the ladle, and ferroalloys are loaded into the bottom of the induction furnace before being filled with metal. Sources of information taken into account during the examination 1. German patent 1263042, cl. 18 in 1/02, 1968. 2. The patent of Germany tf 1508296, cl. C 21 C 5/52, 1972.