NL8820964A - METHOD OF PREPARING STEEL FOR GENERAL PURPOSES. - Google Patents

Description

METHOD OF PREPARING STEEL FOR GENERAL PURPOSES THE APPLICANT HAS INVENTED AS INVENTORS: 1. Anatoly Yakovlevich NAKONECHNY, 2. Manat Zhaxybergenovich TOLYMBEKOV, 3. Alexandr Georgievich PONOMARENKO, 4. Vladimir Geigorievich MIZIN, 5 · Alexandr Jurievich ZAITSEV, 6. Vitalunikiev Lidia Nikolaevna KOLOGRIVOVA, 8. Jury Fedorovich VYATKIN, 9. Alexandr Anatolievich TROYANSKY, 10. Veilentina Mikhailovna PEVTSOVA, 11. Anatoly Vasilievich PETROV, 12. Evgeny Nikolaevtch BELCHENKO, 13 · Vasily Serafimovich K0LPAK.

Field of technology

The present invention relates to meteillurgy and more particularly to a process for preparing general purpose steel.

General purpose steel is understood to mean a steel containing, by mass #: carbon - 0.05 - 0.50 manganese - 0.25 - 2.50 iron - balance.

In addition, general purpose steel may also contain, in bulk #: silicon - up to 0.60 aluminum - up to 0.08 chromium - up to 2.00 vanadium - up to 0.20 titanium - up to 0.20 and other elements.

The invention can be used in the preparation of general purpose steel in a converter, Siemens martin oven and electric oven.

The present invention can be most efficiently used for the preparation of manganese-containing steel.

State of the art

Today, practice is widely practiced around the world in off-kiln steel-making methods (e.g., in the ladle) aimed at improving the quality of the metal obtained in a steel-making process. thing complex.

In addition to alloying and modification with various elements, the ladle also purifies a liquid metal from sulfur, phosphorus, hydrogen, nitrogen and other elements.

Usually the steel purification is not combined with an alloy, but these treatments are carried out one after the other; first steel is alloyed in the ladle by adding various ferroalloys containing alloying elements, and then the metal is purified by blowing with various desulfurizing substances, after which the steel is degassed.

Each of the above treatments involves heat losses, as a result of which the steel treatment outside the furnace to compensate for the heat losses requires either an overheating of the metal in the steel making complex, which favors the oxidation degree of the metal before parting off and thus the properties of the metal. degrades steel, or requires special equipment for heating the metal in the ladle, which increases the cost of the steel and is not always justified for a general purpose steel.

Known from the prior art is a method of preparing steel in a ladle (SU-A-1.219.65¾) which is carried out by adding the alloying elements in the form of a datolite concentrate or a slag of metallic manganese and rod-shaped aluminum as a reducing agent.

The known method consists in collecting a non-deoxidized carbonaceous semi-product in the ladle and removing oxidizing slag. The alloying elements are introduced into the ladle in the bulk of the metal by comminuting the elements of the datolite concentrate or a metallic manganese slag which in turn are solidified on aluminum bars before being placed in the ladle . The consumption of the materials in the known method is chosen so that the calculated amount of aluminum supplied is greater than the stoichiometrically required amount,

The known method does not ensure the purification of the metal from impurities, in particular from sulfur, which hinders the implementation of the method for the preparation of a fine steel with a low sulfur content.

The inclusion of an alloying element and a rod-shaped reducing agent in the mass of the metal in the ladle with a positive penetration in the mass of the metal leads to a liquefaction of the elements, in particular the manganese and a contamination of the steel with non-metallic inclusions of exogenous character, which is the remains of the waste rock, which is present in the oxidizing materials, which make up an alloying element. All this leads to a decline in the quality of the steel.

The addition of the reducing agent in the form of rods leads to a large loss thereof by combustion due to the interaction with atmospheric oxygen and the contact with iron oxides, which are always present on the surface of the liquid carbonaceous semi-finished product, which reduces the cost of the steel increases.

In addition, the preparation of the rods of the reducing agent by applying a layer of an oxide material containing the alloying elements on the surface of the rods requires further costs, which also increase the cost of the steel.

The use of specially prepared bars for alloying steels entails certain technical difficulties which arise in the preparation and storage of the bars and also limit their scope to the preparation of general purpose steels of a composition of which the manganese content ranges from 0.5 to 2.0%.

The use of aluminum bars with a layer of oxide material applied to them, which contains an alloying element, does not ensure the preparation of a steel with a certain chemical composition with respect to manganese and aluminum, because the combustion of the reducing agent is an uncontrolled process and is dependent of a number of parameters which are poorly or not at all controllable, such as the oxidation, for example the degree of oxidation of the carbonaceous semi-product before parting off, the effect of the secondary oxidation of the carbonaceous semi-product in the course of its transfer from a steel-making complex and after collection via the metal mirror as well as other parameters.

The prior art also discloses a method of alloying steel with manganese (SU-A-1,044,641) consisting of melting a carbonaceous semi-product in a steel-making complex, parting off and collecting the semi-product in a ladle, addition in the ladle on the surface of the liquid semi-finished product of a heat-treated oxide material, which contains low phosphorus manganese slags from the preparation of a ferroalloy (LPS) as an alloying element, aluminum as a reducing agent as well as lime in an amount to preserve the basicity of to ensure the snails equal to 2.0-3.5. Oxygen is then blown over the surface for 3 ~ 30 s and purged with argon.

However, the known method does not ensure the preparation of a fine steel, since the combined admixture of an oxide material, which contains manganese (low phosphorus manganese slag from the preparation of a ferroalloy) as an alloying element, a reducing agent and lime, on the surface of a liquid carbonaceous semi-finished product in the ladle after completion of the collection of the semi-finished product from the steel making complex, and subsequent oxygen blowing complicates the control of the process of alloying the steel with manganese and does not involve a high degree of desulfurization of the metal in the ladle.

A reduction of the sulfur content in the steel is usually achieved by processing a highly deoxidized steel in the ladle or by treatment with desulfurizing agents, such as synthetic purifying slag, calcium or magnesium-containing materials (as a rule powdery) and the like.

Intensification of the contact between the desulfurizing agents and the metallic melt is another necessary condition for the strong desulfurization. Such contact can be achieved during the steel treatment in the ladle, for example by intensive stirring of the metal and the synthetic slag at the start of the collection of the carbonaceous semi-finished product in the ladle, in which the synthetic slag is collected before the collection of the semi-finished products.

If calcium or magnesium-containing desulfurized substances are used, strong contact is achieved by releasing the materials into the bulk of the metal as powders. There are some other methods of improving contact.

Strongly basic slags, which are formed according to the known method after the alloying of the steel with manganese, have a certain capacity for sulphide but do not ensure a strong desulfurization of the steel, because no intensive stirring of the metal with the slags is provided.

The known method therefore does not ensure the preparation of a fine steel with a low sulfur content and does not reduce the cost of the steel.

Supply of oxygen leads to an ineffective consumption of the reducing agent, its combustion, local reoxidation of the metal in the reaction zone of manganese reduction and reduction of sulfide capacity (or sulfur absorbing capacity) of the covering slag, which forms the contamination of the steel favors with oxide and sulfide inclusions, i.e. detracts from the properties and increases the cost of the steel.

A combined admixture of materials in the ladle after collection of the carbonaceous semi-finished product therein reduces the extraction of an alloying element (manganese) which, together with poor control of the degree of the alloying process, degrades the quality of the steel and cost price increases.

The preparation of steel according to the known method is associated with a reduction in the capacity of the steel-making complex compared to the capacity, if the steel is alloyed with a ferroalloy, because the release of all substances into the ladle after collecting the carbonaceous semi-finished product lengthens the alloying process in that additional time is required to melt the materials. This reduces the capacity and makes the steel more expensive.

The oxide material used in the known method, which contains manganese as an alloying material, is expensive and requires a lot of energy, because it can only be obtained in an electric arc furnace and requires a large amount of electric energy as well as significant capital investment in the equipment.

The use of such a material increases the cost of the steel and the increases in the cost are even higher in the degree of manganese extraction is small (80 #) and reducing agent losses are high (up to 20 #).

Moreover, the use of the known method only makes it possible to prepare manganese-containing steel, while steel alloyed with other elements cannot be obtained.

The aspects inherently claimed in the known method limit the use of the method to the preparation of steel and prevent its use for the preparation of fine steel with a low sulfur content.

Summary of the invention

An object of the invention is to provide a process for preparing steel for general purposes, wherein the transfer to a ladle is carried out in such a manner with oxide materials containing alloying elements, a reducing agent and desulfurizing substances, which improve the quality of the steel would improve due to reduced sulfur content and non-metallic inclusions and make the preparation cheaper.

This object of the present invention is achieved in that in a general purpose steel preparation process consisting of melting a carbonaceous semi-product in a steel making complex, transferring the product into a ladle, dispensing desulfurizing agents into the ladle, reducing agent and thermally pretreated oxide materials containing alloying elements, the reducing agent of the invention is introduced into the ladle in portions, with a first portion along with the desulfurizing agents during the transfer of no more than one third of the mass of the carbonaceous semi-product into the ladle is dispensed and the other portion before completion of transferring the carbonaceous semiproduct into the ladle is provided along with the thermally pretreated oxide materials containing the alloying elements.

The use of thermally pretreated oxide material decreases the saturation of the steel with gas, because in the course of the thermal treatment the moisture present as hydrate is almost completely removed from the oxide material.

It is thanks to a reduction in the saturation of the steel with gas during the treatment of the steel in the ladle that no subsequent degassing of the steel or removal of gases is otherwise required.

A reduction in the content of gases, such as hydrogen and nitrogen in the steel, improves the quality of the finished steel, because its sensitivity to foaming ("its f lokene-sensivity" *) and contamination with non-metallic nitride phosphorus- inclusions less.

The thermal treatment of the oxide material leads to the destruction of carbonate compounds, which are present in an untreated material. The use of heat-treated oxide material in the treatment of steel alloyed with other elements therefore eliminates the foaming of the forming common slag and its eruption from the ladle and significantly reduces the content of non-metallic inclusions in the finished product. steel. This improves the quality of the steel and eliminates the need for additional purification of the steel from non-metallic inclusions.

In addition, in the course of the thermal treatment of the oxide material, low-melting oxides of high valence containing the alloying elements decompose and oxides of lower valence, i.e., mineral-bound oxygen, are partially removed. This process is even more effective under reducing conditions of the heat treatment.

A reduced oxygen content in the oxides containing the alloying elements reduces the consumption of the reducing agent in the course of alloying and thus improves the quality of the finished steel due to a reduced content of non-metallic oxide inclusions and makes the steel cheaper .

The release of thermally pretreated materials into the ladle accelerates the melting of the oxide material and favors the formation of a homogeneous liquid slag, thereby increasing the possibilities of controlling steel preparation and improving the quality of the finished steel.

Partial provision of the reducing agent in the ladle in the course of transferring the carbonaceous semi-finished product therein makes it possible to control the degree of oxidation of the semi-finished product, that is, to reduce the oxygen content, greatly reducing the degree of desulfurization of the steel affects.

The release of the reducing agent into the ladle in a single amount regardless of the time of addition (at the beginning, in the middle or after transferring the carbonaceous semi-finished product) will impair uniform deoxidation of the carbonaceous semi-finished product and reduce the desulfurization rate .

A combined feed of the first part of the reducing agent with desulfurizing agents allows the carbonaceous semiproduct to be effectively deoxidized in the course of its transfer and favors accelerated melting of the desulfurizing agents, which favors a more complete interaction between the substances with the molten metal and a rational consumption of the reducing agent.

This takes place due to the fact that the reaction of the reducing agent with oxygen (for example dissolved in the mass of the carbonaceous semi-finished product) is exothermic, that is to say under heat development. The heat is consumed to accelerate the melting of the desulfurizing substances and thus to initiate the desulfurization reaction of the metal more quickly. Accelerated homogenization of the desulfurizing agents makes their interaction with the metal last longer, while the metal is vigorously agitated by the jet of the carbonaceous semiproduct falling into the ladle. All this enhances the desulphurisation degree of the steel and improves its quality.

Sulfides and oxisulfides formed in the desulfurization reaction rise to the surface of the metal melt where they give rise to covering slag. The slag protects the surface of the melt from secondary oxidation, reduces the consumption of the reducing agent and reduces the content of non-metallic inclusions.

All this improves the quality of the steel and makes it cheaper.

If the reducing agent and the desulfurizing agents were added separately, this would lead to a deterioration of the technological parameters of steel making; incomplete desulfurization due to longer-lasting homogenization of the desulfurizing agent and increased reductant consumption and consequent contamination of steel with non-metallic oxide inclusions. All this makes the quality of the finished steel worse and makes it more expensive due to the increased consumption of the reducing agent and the desulfurizing substances.

The release in the ladle of the first part of the reducing agent together with the desulfurizing substances during the transfer of not more than 1/3 of the mass of the carbonaceous semi-product ensures effective desulfurization of the metal due to simultaneous occurrence of processes, such as melting of the supplied materials, deoxidation of the metal and desulfurization of the metal. This is also favored by a strong stirring movement of the carbonaceous semi-product with the reducing agent and the desulfurizing agents in the ladle due to the high kinetic energy of the downward jet of the carbonaceous semi-product and the convective flows of the metal, which due to the energy of the beam.

In addition, when the materials are introduced into the ladle simultaneously, homogeneous molten slag appears on the surface of the carbonaceous semi-finished product, if the ladle is filled to no more than 1/3; the molten slag has a high sulfur absorption capacity and inhibits the secondary oxidation of the metal with atmospheric oxygen through the surface of the metal.

All this leads to an effective desulfurization of the metal, improves the quality and makes the finished steel cheaper.

If the first part of the reducing agent and the desulfurizing agent are introduced into the ladle after transferring more than 1/3 of the mass of the carbonaceous semi-finished product, the energy of the falling carbonaceous semi-finished steel is absorbed by the mass of the product in the ladle, the convective processes of agitating the metal with the materials supplied become considerably less intense, the rates of deoxidation and desulfurization of the metal drop sharply, resulting in an increase in the consumption of the material , the quality of the finished steel deteriorates and its cost increases.

The release of the second part of the reducing agent together with the thermally pretreated oxide materials containing the alloying elements make it possible to carry out the process of alloying the steel with minimal consumption of oxide materials and reducing agent and effective desulfurization of the metal.

This is attributed to the fact that favorable conditions prevail in the ladle for alloying and desulfurizing until the reducing agent and oxide material is supplied. The oxygen content in the metal is much lower than in the carbonaceous semi-finished product, which is transferred to the ladle, due to a preliminary deoxidation of the metal after incorporation of the first part of the reducing agent. Under such conditions, the consumption of the reducing agent is economical because the reducing agent is almost entirely consumed for the reduction of the alloying element from the oxide material.

In addition, molten slag which has formed on the surface of the metal at the time of feeding the second part of the reducing agent and the oxide material protects the metal from secondary oxidation and hinders the interaction of the second part of the reducing agent with atmospheric oxygen. The molten slag, due to its sulfur-absorbing capacity, actively desulfurizes new amounts of the carbonaceous semi-product which is transferred to the ladle. The treatment of the steel thus consists of the simultaneous treatment of the steel by alloy using the oxide materials and a purification thereof of sulfur.

All this improves the quality of the steel thanks to a reduction in the sulfur content and makes the finished steel cheaper thanks to an economical use of the reducing agent and of thermally pretreated oxide material, which contains an alloying element.

Separate release of the second portion of the reducing agent and oxide material containing an alloying element would contradict the above described steel preparation process.

If the oxide material is released first, it begins to melt prematurely and mixes with the forming covering slag and dilutes with the molten slag; in addition, the content of the oxides containing the alloying element decreases in the reaction zone and the alloying process takes longer and becomes less complete in terms of extraction of the alloying element in the steel. In addition, the desulfurization process of the metal deteriorates due to an increased content of oxides containing the alloying element in the composition of the molten coating slag. This degrades the quality of the steel, requires additional consumption of the oxide material containing the alloying elements, and of the desulfurizing agent and then of the reducing agent, which makes the steel more expensive.

This degrades the quality of the steel due to the necessity of additional consumption of the oxide material containing alloying elements, and of the desulfurizing agent and additionally of a reducing agent which also makes the steel more expensive.

The inclusion in the ladle of first the second part of the reducing agent and then of the oxide material containing the alloying element leads to an uneconomical consumption of the reducing agent, its possible appearance on the surface of the molten slag after melting and its interaction with atmospheric oxygen.

This makes the quality of the steel worse due to the increased content of non-metallic oxide inclusions and increases the cost of the finished steel due to an increased consumption of the reducing agent. In addition, the handling of the steel becomes more complicated, which can lead to the preparation of steel with an uncontrollable chemical composition.

The release of all material into the ladle before transferring the carbonaceous semi-finished product therein does not reduce the production ability of a steel making complex as compared to alloying steel using ferroalloys.

A combination of the steel alloying and sulfur purification processes not only improves the quality of the finished steel but also reduces its cost, as it eliminates the purification treatment of the steel in special steel purification plants.

A combination of alloying and desulfurization proposed in the present invention is possible only if all materials are released into the ladle before the carbonaceous semi-finished product is transferred therein.

If the portion of the materials, for example, the second portion of the reducing agent together with the thermally pretreated oxide material containing the alloying elements, is placed in the ladle after the transfer of the carbonaceous semi-finished product therein is completed, the alloying process becomes poorly controllable and the desalination process can be stopped if no special measures are taken, such as additional heating, the formation of a neutral or reducing environment on the surface of the molten slag and the like, which make the finished steel more expensive.

This occurs because upon release of the materials into the ladle after the transfer of the carbonaceous semi-finished product therein, the kinetic conditions of the stable preparation in the ladle are completely changed due to the absence of the stirring movement of the metal in the ladle by the downward radius of the carbonaceous semi-product. The absence of stirring motion makes the transport processes in the reduction and desulfurization zone much more complicated, that is, the removal of the reducing element from the oxide melt and of the oxide conversion products from the reaction zone. The alloying and desulfurization processes are beginning to become limited to diffusion of the starting components and the conversion products. Both reactions slow down considerably. The temperature and concentration gradients of the starting components, namely oxides, containing alloying elements, and of the components of the molten slag, which have a high sulphide capacity, prevail in the molten slag, also favor the delay of the reactions. Most of the above components accumulate in the top layers of the molten slag and not in the reaction zone. The top layer of the metal melt, which is saturated with a molten reducing agent, is extensively diluted with a reducing alloying element. As a result, a sharp change in the value of the partitioning coefficient of the alloying element occurs between the slags and the metal, the activity of the alloying element in the slags decreases, and consequently the reduction rate decreases, the possibility of controlling of the alloying process and it becomes difficult to obtain a steel with a predetermined chemical composition. All this makes the quality of the finished steel worse and increases its cost price.

It is advisable to use an aluminum-containing material as a reducing agent.

The physicochemical properties of aluminum and its economical application make aluminum one of the optimal materials widely used in the thermal reduction processes of metals. Aluminum's affinity for oxygen is much higher than that of silicon or carbon, which favors a more complete extraction of the alloying element from the molten slag. Aluminum oxide, as a product of the oxidation of aluminum, reduces the activity of the alloying element in the molten slag to a much lesser extent than silicon oxide, the product of the oxidation of silicon. Silicon oxide is a very strong acidic oxide, and to neutralize it in the reduction process, basic oxides of calcium, magnesium and other elements are usually included in the molten slag. Such additives not only require an additional energy consumption for melting and heating to their required temperature, but dilute the molten slag, thereby somewhat reducing the activity of the alloying element in the slag. All this detracts from the desulphurisation processes of steel, reduces the extraction of the alloying element from the molten slag, contaminates the steel with non-metallic inclusions, degrades the quality of the finished steel and makes it more expensive.

The use of aluminum as a reducing agent also favors the thermal character of the process to a greater extent than the use of silicon and, if necessary, also allows the molten slag to contain the corresponding slag-forming and desulfurizing substances, for example lime, without the use of additional heat carriers for melting the lime.

An additional inclusion of the desulfurizing agents without additional energy consumption for melting increases the sulfide capacity of the molten slag, reduces the sulfur content in the finished steel immediately as the carbonaceous semifinished product is transferred into the ladle and eliminates an additional desulfurization treatment of the steel in special installations. This improves the quality of the finished steel and reduces its cost price.

It is desirable to use an alloy based on aluminum, calcium and silicon as the reducing agent.

The inclusion of silicon and calcium in the composition of the aluminum-containing reducing agent not only enhances the deoxidation of the carbon-containing melt, but also favors the desulfurization of the melt. The difference in physico-chemical properties of these elements is fully utilized in the proposed process. Silicon has a higher density than aluminum and, when incorporated in the ladle, favors deoxidation of the carbonaceous semi-product at a greater depth even in a calmed metal. If the carbonaceous semi-product is kept in stirring motion by the falling jet, this effect is enhanced. At prevailing temperatures of the metal melt in the ladle, ranging from 1550-16020 ° C, silicon does not form gaseous oxidation products, such as, for example, calcium, magnesium and to some extent aluminum. The silicon losses due to its interaction with atmospheric oxygen are therefore negligibly small.

This contributes to the economical use of silicon and therefore favors the possibility of controlling the steel preparation in the ladle, improves the quality of the finished steel and makes it cheaper.

Calcium in the alloy composition, which is incorporated into the ladle along with other alloy components, namely aluminum and silicon, not only increases the deoxidizing capacity of the alloy, but also increases the desulfurization rate of the metal melt and favors the formation of the covering molten slag with a high sulphide capacity. A high vapor pressure of calcium at high temperatures (1550-160 ° C) attributed to the formation of gaseous calcium products is utilized in the proposed invention to desulfurize the metal melt without significant gaseous phase calcium losses. This is due to the fact that the calcium activity in the alloy is greatly reduced by the presence in the alloy of other components, namely aluminum and silicon. In addition, the density of the alloy is much higher than that of pure calcium; the melting of the alloy therefore takes place in the mass of the metal melt and not on its surface, which favors the degree of efficient utilization of the calcium.

Thus, the use of the alloy improves the quality of the steel due to a reduced sulfur content and makes the steel cheaper thanks to an economical utilization of the alloy and a reduction of its losses due to the lack of interaction with oxygen in the atmosphere.

It is desirable to use a mixture based on aluminum, calcium and iron as the reducing agent.

The inclusion of iron in the mixture increases the density of the mixture and therefore favors a deeper penetration into the mass of the metal or molten slag. Thanks to an increased density of the mixture compared to the density of the reducing components, the losses of the reducing agent decrease, because the interaction with atmospheric oxygen decreases, the content of non-metallic inclusions in the steel decreases, the degree of desulfurization of increases the quality of the steel and reduces its cost.

The mixture which, in the course of transferring the carbonaceous semi-finished product into the ladle together with the desulfurizing substances and then with the heat-treated oxide material containing the alloying elements and having high deoxidizing and desulfurizing activities as well as increased density, it is possible to combine the transfer of the carbonaceous semi-product with the deoxidization of this semi-product, its purification of sulfur and its alloying.

The application of the proposed mixture intensifies the steel preparation in the ladle, improves the quality of the steel immediately after casting without further treatment using special equipment. This reduces the cost of the finished steel.

It is useful to use manganese-containing oxide materials which have been thermally pretreated at temperatures of 900 to 1250 ° C as the thermally pretreated oxide materials.

The use of heat-treated oxide materials, whatsoever, precludes gas development in the course of melting upon contact with the metal melt and eliminates foaming of the molten slag. In the absence of gaseous products of dissociated oxides in the molten slag contributes to effective use of the reducing agent, reducing losses of the reducing agent due to an interaction with oxygen contained in the composition of the dissociated components improves the quality of the steel, thanks to a reduced oxide content and non-metallic oxidesulfide inclusions, makes the finished steel cheaper, as no additional measures to improve operating conditions due to personnel are necessary and no unjustified use of the reducing agent is required.

If one takes into account the fact that manganese is present in the composition of most grades of general purpose steel in amounts ranging from 0.2 to 2.0 mass #, the wide application possibilities of the proposed process become apparent.

A choice of temperature for the pre-treatment of a manganese-containing oxide material is determined by the fact that virtually all manganese ores used in metallurgical processes, except hydrates such as moisture, contain carbonate compounds of manganese and other elements.

The use of the so-called "crude" ore in pyrometallurgical processes is therefore accompanied by the release of gas, which often results in the eruption of liquid slag and metal from a steel making complex or ladle.

The use of manganese-containing oxide materials, which have been thermally treated at temperatures below 900 ° C, leads to an increased consumption of the reducing agent, the losses of which increase during the release of gas. As a result, the degree of manganese reduction from the molten slag decreases, the steel becomes contaminated with non-metallic inclusions; thus deteriorating the quality of the finished steel and increasing its cost.

The thermal treatment of manganese-containing oxide materials at 900 ° C and above ensures the destruction of all carbonate forms of the minerals present in the manganese ore, and facilitates the transition of the manganese into oxides with a lower oxygen content, thereby reducing the consumption of the reducing agent is reduced, the manganese extraction from the molten slag is increased, the quality of the steel is improved and its preparation becomes cheaper.

A thermal treatment of manganese-containing oxide materials at a temperature above 1250 ° C causes the formation of barely reducible manganese silicates, such as Mn2SiCty (tefroite) or MnSiOg (rhodonite).

In addition, if the thermal treatment is carried out at temperatures above 900 ° C, the melting point of the prepared material increases, which adversely affects the completeness of the reduction and facilitates contamination of the steel with non-metallic inclusions, i.e. the quality of the steel deteriorates and its cost price increases.

It is expedient to deliver the thermally pretreated manganese-containing materials into the ladle in a jet of neutral gas while the metal melt is heated.

Such release ensures a sufficiently complete extraction of manganese from the manganese-containing material even during the transfer of the carbonaceous semi-product into the ladle.

The combination of the release of the heat-treated oxide material with simultaneous heating of the metal melt in the ladle makes it possible to receive solid slag-forming and desulfurizing substances in the ladle. This improves the quality of the steel thanks to a reduced sulfur content and makes the steel cheaper thanks to an economical use of the heat-treated manganese-containing oxide material.

The release into a ladle of a heat-treated manganese-containing oxide material in a neutral gas jet, not in the mass of the metal melt, but, for example, on the surface of the melt, reduces the degree of manganese reduction but substantially reduces the desulfurization of the metal melt, increases the losses of the reducing agent due to its interaction with atmospheric oxygen, increases the content of non-metallic inclusions in the steel. All this can make the quality of the steel worse and increase its cost price.

Omitting the heating of the metal melt in the course of adding the heat-treated oxide material into the jet of the neutral gas would lower the temperature of the metal melt due to the cooling of the melt with the cold oxide materials and the neutral gas. This would give rise to the necessity of additional heating of the carbonaceous semi-finished product in a steel making complex, re-oxidation of the semi-finished product and thus an increased consumption of the reducing agent, an increase in the amount of non-metallic inclusions in the steel and a deterioration of the quality of the steel.

Moreover, the degree of manganese reduction may decrease due to the fact that the particles of the heat-treated manganese-containing oxide material, which find their way into the mass of the metal, may incompletely melt at the reduced temperatures of the metal at the interface between the metal and the molten slag can occur and are taken up by the molten slag. This would lead to an increased content of manganese oxides in the molten slag and a reduction in its sulfide capacity. As a result, the desulfurization of the molten slag may deteriorate, the quality of the finished steel may deteriorate and its cost price increase.

It is desirable to use as a desulfurizing agent a slag-forming mixture which is dispensed into the ladle in a selected amount in a ratio of the mixture to the reducing agent supplied in the first portion successively (1.0-1.1) : (0.20-0.30).

The addition of the reducing agent and the slag-forming desulfurizing mixture at the start of transferring the carbonaceous semi-product to the ladle reduces the dissolved oxygen concentration in the carbonaceous semi-product, making the conditions favorable for desulphurization of the metal melt and the contact surface between the metal and the molten slag greatly increased.

An increase in the contact area between the slag and the metal melt is ensured by both strong convective currents of the metal melt, which are generated by the energy of the downward jet of the carbonaceous semi-product and by the jet as such, which in the course of the transferring 1/3 of the mass of the carbonaceous semi-finished product into the ladle is capable of introducing the slag-forming desulfurizers into the mass of the metal.

In addition, a simultaneous supply of the reducing agent with the slag-forming desulfurizing mixture eliminates the burning of the reducing agent due to the coating of the surface of the metal with a slag layer. This reduces the consumption of the reducing agent due to its small losses, reduces the amount of non-metallic inclusions in the steel and thus improves the quality of the steel and makes it cheaper.

The amount of the slag-forming desulfurizing mixture and the reducing agent selected from the ratio of the amounts of the mixture and the reducing agent supplied in the first portion is equal to (1.0-1.1) :( 0.20-0.30 ) allows to have in the ladle a deoxidized metal and a liquid slag layer on the surface of the metal, which provides favorable conditions for the desulfurization of the steel.

If the consumption of the reducing agent becomes less than the predetermined value, the degree of deoxidization of the metal melt, that is, the oxygen content therein, may not decrease sufficiently. This reduces the desulfurization degree.

If the consumption of the reducing agent exceeds the predetermined value, the content of non-metallic inclusions in the steel increases and thus the quality of the steel deteriorates and the cost increases due to non-economic consumption of the materials.

If the ratio of the amounts of the slag-forming desulfurizing mixture and the reducing agent changes towards a reduction in the use of the slag-forming mixture, the desulfurization capacity of the molten slag and its sulfide capacity decrease, while an increase in the consumption of the slag-forming mixture above a predetermined value makes the homogenization process of the mixture take longer due to the fact that the desulfurization degree decreases and thus the quality of the steel deteriorates and its cost increases.

When the second portion of the reducing agent is supplied, it is desirable to simultaneously add a further amount of the desulfurizing agents.

The feed described ensures the combination of the processes of deoxidation of the carbonaceous semi-finished product, alloying of the product and simultaneous desulfurization, which ensures economical use of the materials and the preparation of a cheap high-quality steel. The simultaneous release of all materials into the ladle ensures intensive deoxidation of the carbonaceous semi-product before melting the oxide materials containing the alloying elements and desulfurizing the materials. All this ensures favorable conditions for the reduction of the alloying elements from the molten slag and for the desulfurization of the metal,

The presence of the desulfurizing and oxide materials containing the alloying elements on the surface of the metal melt protects the metal melt from secondary oxidation, thereby ensuring favorable conditions for economical use of the reducing agent, which will burn due to interaction with atmospheric oxygen is almost completely excluded.

Since the melting point of the reducing agents is always lower than that of the oxide materials containing the alloying elements, the melting of the reducing agents in the bulk of the metal melt occurs at a higher rate than that of the oxide materials. Therefore, at the time of melting of the oxide materials containing the alloying elements, the concentration of the reducing agent in the metal melt is high enough and the reduction process of the alloying elements from the molten slag proceeds at a high speed, which is extremely important for the treatment of steel in the ladle, whereby an increase in the treatment time is accompanied by large heat losses and an additional consumption of heat carriers.

An increase in the reduction rate is also favored by an excess of heat, which is generated in the reduction reaction and is mainly consumed to melt the desulfurizing and oxide materials containing the alloying elements. This is due to the fact that the reduction reaction is exothermic when metallic reducing agents are used. This is accompanied by an intensive melting of the desulfurizing substances and thus with an increase in the sulphide capacity of the covering slag.

Economical use of the reducing agent reduces the content of non-metallic inclusions in the steel, improving the quality of the finished steel and making it cheaper to manufacture.

A separate supply of the materials into the ladle conflicts with the above-described method. The release of the second amount of the reducing agent alone causes large losses of the reducing agent due to an interaction with atmospheric oxygen, a contamination of the steel with non-metallic inclusions, and poor desulfurization conditions. Since a high consumption of the reducing agent is primarily intended for the reduction of the alloying elements from the molten slag, due to the absence of the oxides of the alloying elements, the occurrence of a large amount of the reducing agent after melting appears on the surface of the molten slag and is available to interact with atmospheric oxygen, contaminating the metal melt with non-metallic inclusions and degrading the quality of the steel. Moreover, at the time of the release of the oxide materials containing the alloying elements, a large part of the reducing agent has already been consumed and the reduction process of the alloying element from the slags is deteriorating. This makes the thermal conditions for melting the desulfurizing material less favorable, as a result of which the desulfurization process of the metal melt degenerates.

The release in the ladle of first an oxide material, which contains the alloying elements, and then of other substances, causes the reduction and desulfurization processes of the metal melt to deteriorate. This is due to the fact that the molten oxide material mixes with the covering slag, which leads to a decrease in the concentration of the oxides of the alloying elements and thus a deterioration of the reduction conditions. The conditions for the desulfurization of the metal melt also deteriorate, because an increased content of the oxides of the alloying elements in the molten slag promotes a redistribution of oxygen between the slag and the metal, an increase in the oxygen content in the metal melt and a deterioration of the quality of the steel.

It is desirable to use dolomite as a desulfurizing agent, which is also included in the ladle, the amount of dolomite being selected in the ratio of dolomite to reducing agent released in the second portion, equal to 0.8-1.2.

The inclusion of dolomite together with the second portion of the reducing agent allows the combustion (losses) of the reducing agent due to its interaction with atmospheric oxygen to be almost completely eliminated and facilitates a more complete reduction of the alloying elements from the molten slag. In this case, the dolomite incorporated in the ladle forms a protective layer on the surface of the molten slag, which prevents the reductant from appearing on the surface of the molten slag and interacts with atmospheric oxygen.

A maximum deoxidized layer of the molten slag is formed at the metal-slag interface, and the sulfide capacity of the molten slag increases sharply. As a result, favorable conditions are set in the ladle for desulphurisation of the metal melt, which improves the quality of the steel and reduces its cost.

In addition, a highly deoxidized layer formed near the surface in the molten slag is reliably shielded by the top layer of the molten slag from secondary oxidation, since the incorporation of dolomite into the ladle together with the second portion of the reducing agent form the facilitates an upper refractory layer of the molten slag. This also improves the quality of the steel and makes it cheaper.

If the second portion of the reducing agent is supplied without dolomite, the reducing agent losses increase because the reducing agent, after melting, comes to the surface of the molten slag and is lost by oxidation with atmospheric oxygen. This leads to a secondary oxidation of the metal melt with atmospheric oxygen. As a result, the desulfurization degree of the steel decreases, the content of non-metallic inclusions increases, and thus the quality of the steel deteriorates and its cost increases.

If dolomite is supplied without the second portion of the reducing agent, the desulfurization conditions of the metal melt will deteriorate substantially, because the degree of deoxidization of the metal melt remains unchanged at the time of dolomite addition and the sulfide capacity of the molten slag decreases due to the increasing viscosity. This makes the quality of the finished steel worse and makes it more expensive.

The inclusion of dolomite in the amount selected in a ratio between the amounts of dolomite and reducing agent released with the second portion equal to 0.8-1.2 allows deoxidizing the metal and thickening the surface layer of the molten slag .

If the amount of dolomite is less than the predetermined ratio, no thickening of the top layer of the molten slag occurs, resulting in the consumption of the reducing agent is uneconomical, the reducing agent is lost due to interaction with atmospheric oxygen, the degree of deoxidation of the metal melt decreases, the desulphurization degenerates and thus the quality of the steel becomes poor and the cost price increases.

If dolomite is included in amounts greater than the above-mentioned ratio, the molten slag becomes completely thickened and can no longer play a role as desulfurizing agent, which degrades the quality of the steel and makes the steel more expensive.

If the consumption of the reducing agent becomes less than the predetermined ratio, the degree of deoxidization and thus the desulfurization degree of the steel decreases; if the consumption of the reducing agent exceeds the predetermined ratio, the reducing agent dissolved in the metal melt causes the supersaturation of the melt above the concentrations required for any steel grade and the predetermined chemical composition of the steel cannot be reached. This affects the quality of the steel and makes it more expensive.

It is expedient to use calcium carbide as a desulfurizing agent which is supplied in portions. The first portion of the calcium carbide is released together with the first portion of the aluminum-containing material and lime in an amount selected in the ratio of lime to aluminum in the aluminum-containing material and to the calcium carbide of successively equal to (4.0-5.0): (0.3-0.6) :( 1.5-2.0), while the calcium carbide released with the second portion of the aluminum-containing material is used in an amount selected in the ratio of aluminum in the aluminum-containing material to calcium carbide equal to successively (1.0-1.2) :( 2.5-3.6).

The release of the slag-forming materials at the start of transferring the carbonaceous semi-finished product into the ladle ensures maximum contact surface area of the metal with the slags, and the addition of the aluminum-containing materials provides proper deoxidation of the metal melt, which provides the conditions for the improves desulfurization of the metal melt, calcium carbide as such in the deoxidized metal being a good desulfurization agent.

The release of lime along with the aluminum-containing material and calcium carbide increases the sulfide capacity of the slags formed on the surface of the metal melt. This improves the quality of the steel due to a reduced sulfur content and a smaller amount of non-metallic inclusions, while the cost of the steel decreases.

A reduction in the use of lime below the claimed ratio increases the melting point of the slag due to an insufficient fluxing action of calcium carbide, decreases the degree of desulphurisation and compromises the quality of the metal. In addition, due to a small amount of the slags, a strong secondary oxidation of the metal melt occurs on the surface not protected by the slags. This increases the oxidation and consumption of aluminum, facilitates the formation of a large amount of non-metallic inclusions in the mass of the metal melt, impairs desulfurization and thus degrades the quality of the steel and makes the steel more expensive.

An increase in lime consumption above the claimed ratio is also unsuitable, as it leads to a decrease in the concentration of calcium carbide in the molten slag, in the sulfide capacity of the slag and in the degree of desulfurization, which results in a deterioration in the quality of the steel. The degree of extraction of the alloying element from the molten slag decreases and the steel becomes more expensive.

A reduction in the consumption of the aluminum-containing material to below the claimed ratio leads to an insufficient deoxidation of the metal melt, an increased solubility of sulfur therein and thus to a reduced degree of desulphurisation, deterioration of the quality of the steel and higher cost thereof.

An increase in the consumption of the aluminum-containing material above the claimed ratio is also unsuitable, since the incorporation of the material into the metal melt gives rise to the melting of aluminum and its oxidation with atmospheric oxygen. This increases the content of non-metallic inclusions in the steel, decreases the quality of the finished steel and makes the steel more expensive due to a non-economic consumption of the aluminum-containing material.

Reducing the consumption of calcium carbide below the claimed ratio decreases the sulfide capacity of the molten slag and thus compromises the quality of the steel.

An increase in the consumption of calcium carbide above the claimed ratio increases the melting point of the molten slag and thus increases the viscosity, as a result of which the desulfurization capacity of the molten slag decreases, the quality of the steel deteriorates and the cost increases.

The release into the ladle of the second portion of the calcium carbide together with the thermally pretreated oxide materials containing the alloying elements and the aluminum-containing materials during the transfer of the carbonaceous semi-product ensures simultaneous alloying and desulfurization of the metal melt . This is achieved by the functional distribution of the materials delivered into the ladle. The addition of calcium carbide increases the sulfide capacity of the molten slag, thereby favoring the degree of desulphurisation of the metal melt. Simultaneous release of the thermally pretreated oxide materials containing the alloying elements and of the aluminum-containing materials ensures the process of alloying the metal melt and further oxidation of the metal melt, which also favors desulfurization. All this improves the quality of the steel and makes it cheaper.

A reduction in the consumption of calcium carbide to below the claimed ratio reduces the sulfide capacity of the molten slag and the degree of desulphurisation and thus degrades the quality of the steel.

An increase in the consumption of calcium carbide above the claimed ratio leads to a thickening of the molten slag, decreases the desulfurization rate and thus degrades the quality of the steel and makes it more expensive.

A reduction in the consumption of the aluminum-containing material below the claimed ratio leads to an insufficient deoxidation of the metal melt, a reduced degree of desulfurization and a deterioration in the quality of the steel. Moreover, the degree of reduction of the alloying element from the molten slag decreases, which also leads to a deterioration in the quality of the steel and an increase in its cost price.

An increase in the consumption of the aluminum-containing material above the claimed limit makes the steel more expensive due to a non-economic consumption of the material and makes the quality of the steel worse, because the aluminum content can rise above the predetermined limits for a certain steel quality.

The proposed technology thus provides an improvement in steel quality and a reduction in its cost.

Preferred embodiment of the invention

The general purpose steel preparation process is carried out in the following manner.

A carbonaceous semi-product, for example, having the following chemical composition (in mass #): carbon - 0.05-0.30 manganese - 0.05-0.10 slicium. . V trace amounts of aluminum j sulfur - up to 0.0300 phosphorus - up to 0.025 iron - residue is melted in a steel making complex; As a steel-making complex, any known complex can be used, for example a Siemens-Martin oven, electric oven or a converter with oxygen blowing, gas-oxygen mixtures, neutral and other gases at the top, bottom or combined.

A selection of a steel making complex for the preparation of the carbonaceous semi-finished product according to the proposed process is determined by the requirements of the general purpose steel and can be determined according to the production plan of the steel making.

The carbonaceous semi-finished product prepared in the steel-making complex is poured into the ladle with a capacity corresponding to or more than the capacity of the steel-making complex.

In the course of pouring the carbonaceous semi-finished product into the ladle, the desulfurizing substances (lime, mixtures based on lime, dolomite, calcium carbide and / or others) are also introduced therein.

As soon as the ladle is filled with no more than 1/3 of the mass of the carbonaceous semi-finished product, the first part of the reducing agent is fed together with the desulfurizing substances.

The second portion of the reducing agent is released simultaneously with the thermally pretreated oxide materials containing the alloying elements. All substances are released before the transfer of the carbonaceous semi-finished product into the ladle is completed.

As thermally pretreated oxide materials containing the alloying elements, manganese-containing materials as well as chromium, vanadium, titanium and other materials can be used, which are delivered individually or in combination in the ladle depending on the predetermined chemical composition of the prepared steel.

The supply of the thermally pretreated oxide materials containing the alloying elements is stopped before transferring the carbonaceous semi-finished product into the ladle.

As the reducing agent, alloys and mixtures based on aluminum, calcium, silicon, iron, titanium and the like can be used. As a result, the steel with the predetermined chemical composition is obtained.

The use of thermally pretreated oxide materials makes it possible to completely exclude foaming of the molten slag in the ladle and to prevent splashing and ejection of the metal and slag from the ladle during the transfer of the carbonaceous semi-finished product. A smooth course of the reduction process and an almost complete absence of moisture as hydrate in the thermally pretreated oxide materials containing the alloying elements made it possible to significantly reduce the oxygen and nitrogen content in the steel prepared, the amount of non- reduce metallic inclusions formed during the foaming of the molten slag, thereby improving the quality of the steel and reducing its cost.

The reduction process of the alloying elements from the thermally pretreated oxide materials, which are introduced into the ladle, is short and ends once the total amount of the carbonaceous semi-finished product has been poured into the ladle. The degree of extraction of the alloying element from the oxide material reaches 90-975 ». which far exceeds the total extraction rate of the alloying element in the case of the use of ferroalloys. All this makes the finished steel cheaper.

The release of the reducing agent in sections into the ladle ensures uniform deoxidation of the carbonaceous semi-product during its transfer, reduces the losses of the reducing agent due to its interaction with atmospheric oxygen, reduces the content of non-metallic inclusions in the steel, facilitates desulphurisation of the metal melt and thereby improves the quality of the steel and makes it cheaper.

If the reducing agent is dispensed into the ladle in a single amount irrespective of the time of addition (at the beginning, in the middle or after decanting the carbonaceous semi-product), the deoxidation process of the carbonaceous semi-product proceeds in a non-uniform manner. In this case, the conditions for the desulfurization of the metal melt are adversely affected and losses due to interaction with atmospheric oxygen increase. The steel becomes contaminated with non-metallic inclusions and the oxidizing products of the reducing agent. All this makes the quality of the steel worse and makes it more expensive.

The release of the first part of the reducing agent together with the desulfurizing agents ensures favorable conditions for the desulfurization of the metal melt, because the deoxidation process is combined with the treatment of the metal melt with desulfurizing agents. In this case, the reducing agent is used economically: almost completely for the deoxidation of the carbonaceous semi-product. This is greatly favored by the presence in the ladle of the desulfurizing substances, which (after melting) form a slag layer on the surface of the metal melt, thus protecting the metal melt from secondary oxidation and the reducing agent from interaction with atmospheric oxygen. All this ensures the preparation of a cheap sample of excellent quality.

The above-described method is violated if the first part of the reducing agent and the desulfurizing agent are released separately into the ladle. A preliminary feed of the reducing agent causes large losses thereof due to the interaction with atmospheric oxygen, which is caused by a direct contact of the molten reducing agent, which has a lower density than the carbonaceous semi-product, and thereby melts on the surface of the metal come into contact with atmospheric oxygen and oxygen from the metal melt, which is continuously accumulated in the melt due to the secondary oxidation.

This detracts from the process of further desulphurisation of the metal melt after release into the ladle of the desulfurizing substances and thus detracts from the quality of the finished steel and makes it more expensive.

The release of the desulfurizing substances into the ladle without the reducing agent does not provide an intensive removal of sulfur from the metal melt, because a high degree of oxidation hinders the desulfurization, which also detracts from the quality of the steel and increases its cost.

The release of the first part of the reducing agent together with the desulfurizing substances during the transfer of 1/3 of the mass of the carbonaceous semi-product ensures an intensive deoxidation of the metal melt and its desulfurization due to the fact that the energy of the downward jet of carbonaceous semi-product at the beginning of its pouring into the ladle gives rise to strong convective flows of the metal melt in the ladle, favoring an intensive stirring of the metal melt with the reducing agent and the desulfurizing agent. This greatly increases the contact area of the metal melt with the desulfurizing agents and reducing agent, which melt in the course of the stirring motion, thereby achieving high degrees of sulfur removal in the slag and deoxidation of the metal melt. In the initial period of pouring the carbonaceous semi-finished product into the ladle, when a slag layer has not yet formed on the surface of the metal melt, the downward jet of the carbonaceous semi-finished product additionally takes the materials supplied to the ladle, namely the reducing agent and the desulfurizing substances, along with the depth of the metal melt. This also increases the contact area of these materials with the metal melt, which improves the quality of the steel thanks to a lower sulfur content, and makes it cheaper.

If the substances are released into the ladle when more than 1/3 of the mass of the carbonaceous semi-finished product has already been transferred, the process of stirring all the materials supplied is greatly reduced, because the kinetic energy of the jet is absorbed by the mass of the carbonaceous semi-finished product already transferred to the ladle. This greatly reduces the degree of desulfurization of the metal melt and the uniformity of the sulfur desulfurization across the height of the ladle. This degrades the quality of the steel and increases its price.

The release of the second part of the reducing agent together with the thermally pretreated oxide materials containing the alloying elements ensures intensive and complete reduction of the alloying element from the molten slag, economical consumption of the reducing agent and interrupts the desulfurization of the metal melt not. This is due to the fact that at the time of feeding the second portion of the reducing agent with the thermally pretreated oxide materials containing the alloying elements, a properly deoxidized low sulfur metal melt is present in the ladle . The reducing agent released into the ladle is therefore mainly used for interacting with the oxides of the alloying elements in the molten slag and only a small amount of the reducing agent is consumed for the deoxidation of a new portion of the carbonaceous semi-product which is added to the ladle is supplied. The layer of the covering slag on the surface of the metal melt, which are formed after the desulfurization previously carried out in the ladle and which increase in mass in the course of the reduction of the alloying elements from the molten slag, reliably react with the surface of the metal melt, thereby protecting it from secondary oxidation, ensuring a reduction of losses of the reducing agent due to interaction with atmospheric oxygen, improving the quality of the steel due to the desulfurization and reducing the content of non-metallic oxide and oxysulfide inclusions. All this reduces the cost of the finished steel.

Separate release of the reducing agent and the thermally pretreated oxide materials containing the alloying elements conflicts with the above-described process and as a result of which the quality of the steel deteriorates and its cost increases.

A prior supply of the second portion of the reducing agent causes a non-economic consumption, because the oxygen content in the metal melt is low until the incorporation of the second portion of the reducing agent and in the molten slag, which has a have high sulfide capacity, hardly readily reducible oxides, such as oxides of iron, manganese, vanadium and the like, are present. The molten reducing agent, the amount of which is chosen taking into account the consumption of the reducing agent for the reduction of the alloying elements, comes to the surface of the molten slag and interacts with atmospheric oxygen. This not only gives rise to a reduction of the reducing agent with a deterioration in the quality of the steel, since after the subsequent release into the ladle of heat-treated oxide materials containing the alloying elements, no complete reduction of the alloying elements is ensured. and the steel becomes more expensive.

The presence in the molten slag of non-reduced oxides of the alloying elements reduces the sulfide capacity of the molten slag and thus impairs the desulfurization process and degrades the quality of the steel.

The release in the ladle of first thermally pretreated oxide materials containing the alloying elements and then of the reducing agent is also not sensible, since the melting of these materials facilitates saturation of the molten slag, which reduces the sulfide capacity of the molten slag. and affects the desulfurization conditions. In addition, some of the oxygen in the composition of the oxides containing the alloying elements passes into the metal melt, which was well deoxidized to date. Further amounts of the carbonaceous semi-product also introduce oxygen into the metal melt. In the absence of the reducing agent, oxygen accumulates in the metal melt, which adversely affects the quality of the steel by increasing the sulfur content and non-metallic inclusions therein. This increases the cost of the steel.

The release of all substances into the ladle before the transfer of the carbonaceous semi-finished product has been completed ensures a strong reduction of the alloying elements from the molten slag without interrupting the desulfurization process. This is accomplished in that in the course of transferring the carbonaceous semi-product, strong convective flows in the mass of the semi-product are induced due to the kinetic energy of the downward jet of the carbonaceous semi-product. The stirring movement of the metal melt during the transfer of the carbonaceous semi-finished product favors the removal of the reducing alloying elements from the reaction zone to the depth of the ladle, which uniformizes the distribution of these elements over the ladle height and enhances the reduction process. . The reduction process of the alloying elements therefore takes place under an intensive kinetic regime at a high speed and is almost complete with the completion of decanting of the carbonaceous semi-finished product.

This also ensures a sufficiently complete extraction of the alloying elements from the molten slag.

The release in the ladle of the second portion of the reducing agent and the thermally pretreated oxide materials containing the alloying elements upon completion of the transfer of the carbonaceous semi-finished product greatly reduces the rate and completeness of the reduction of the alloying element from the molten slag. Unreduced oxides of the alloying elements dissolve in the molten slag, reduce its sulfide capacity, leading to a deterioration in the quality of the steel and an increase in its cost.

It is expedient to use an aluminum-containing material as a reducing agent.

In terms of oxygen affinity, aluminum is the most active element of the materials widely used in metallurgy for deoxidation of steel and reduction processes.

Therefore, an aluminum-containing material, when used economically, is preferred for use in reduction processes. In addition, when aluminum-containing materials are used, the heat of the reduction process increases, making it possible to increase the consumption of desulfurizing substances without additional heating of the metal melt.

High speed of the process is a very important factor for steel casting in a ladle, as an extension of the production process not only reduces the capacity of the steel making complex, which increases the cost of the finished steel, but also requires additional energy consumption to compensate for the heat losses of the metal melt, which are directly dependent on the time of the steel treatment in the ladle.

If additional energy is consumed in the steel-making complex to raise the temperature of the carbonaceous semi-product before transferring it to the ladle, not only does the steel become more expensive, but its quality also deteriorates. This occurs due to the fact that the superheating of the carbonaceous semi-finished product in the steel making complex is usually accompanied by an increase in the oxygen content in the semi-finished product and the reduction of the oxygen content requires the addition of the reducing agent, the interaction of which with the oxygen gives rise to the formation of non-metallic inclusions. An increased amount of non-metallic inclusions degrades the quality of the steel.

The use of another element with high oxygen affinity as a reducing agent is less effective. For example, if ferrosilicon is used, the heat of the reduction process decreases, the amount of acid oxides in the slag increases, which acid oxides form complexes with the oxides containing the alloying element, the activity of the alloying element in the slugs sharply, reduces their extraction rate from the slugs, thereby deteriorating the quality of the steel and increasing its cost. In addition, an increased content of the acid oxides in the molten slag reduces the sulfide capacity of the melt and thus impairs the quality of the steel.

The use of carbonaceous materials as a reducing agent is also less effective, because the reducing reaction of the alloying element from the molten slag is endothermic, that is with heat absorption, the compensation of which requires an additional consumption of energy carriers, which is much greater than the consumption of any metallic reducing agent, because heat is required to melt the thermally pretreated oxide materials containing the alloying elements.

All this reduces the quality of the steel and increases its cost price.

For the preparation of manganese steel of any chemical composition, the oxide material used is a manganese-containing oxide material which has been subjected to a thermal treatment at 900-1250 * 0 beforehand.

A choice of such an oxide material, which contains manganese as an alloying element, was imposed because almost all general purpose steel contains manganese in an amount ranging from 0.25 to 2.5 mass #.

A selection of the temperature range of the heat treatment equal to 900-1250 ° C is imposed by the need to remove moisture present as a hydrate from the oxide material, the presence of which, as noted above, results in foaming of the slag over time. alloying the steel, erupting the metal and slag from the ladle and increasing the contamination of the finished steel with gases such as hydrogen and nitrogen, which impairs the quality of the finished steel.

The thermal treatment of the manganese-containing oxide material at the above temperatures facilitates the decomposition of the carbonate compounds present in these manganese-containing oxide materials, which also facilitate the foaming of the slag and the erups of metal and slag from the ladle as hydrate form moisture. increase the degree of gas saturation of the finished steel with nitrogen and hydrogen and the amount of non-metallic inclusions. All this detracts from the quality of the steel and makes it more expensive due to the need to take further measures for purifying the steel from gases and reducing the amount of non-metallic inclusions.

When heat-treated or manganese-containing oxide materials treated at temperatures below 900 ° C are used, the manganese in the form of dieηθ £ (pyrolusite), Mn ^ Ojj. (Hausmannite) or in the composition of carbonate forms of MnCO 2, CaCO 2 minerals and other types, their release into the ladle is accompanied by the decomposition of the oxide and carbonate components to form gaseous carbon monoxide and dioxide. Gaseous products of the decomposition of the oxide material cause the molten slag to foam in the ladle and favor the erupion of the metal and slag from the ladle. In addition, they favor the transport of atmospheric oxygen in the bulk of slag and metal melt, an increase in the consumption of the reducing agent, and the amount of non-metallic inclusions in the finished steel, thereby reducing the quality of the finished steel and making it more expensive. made.

The thermal treatment of the manganese-containing oxide material at temperatures below 900 ° C does not ensure complete removal of moisture present as hydrate, the presence of which also detracts from the quality of the steel by contamination of the steel with non-metallic inclusions.

It is not wise to carry out the thermal treatment of the manganese-containing oxide material at a temperature above 1250 ° C, because in this case the oxide material takes place, which leads to a change in its physico-chemical properties, in particular some concerns an increase in melting point. This prolongs the reduction process in the ladle and causes it to be less effective to contaminate it after the transfer of the carbonaceous semi-finished product into the ladle.

The thermally pretreated manganese-containing material is placed in the ladle in a neutral gas stream, while the metal melt is simultaneously heated. This favors near-complete extraction of the manganese from the oxide material before transferring the carbonaceous semi-finished product to the ladle.

A combination of the release of the thermally pretreated manganese-containing material with a heating of the metal melt makes it possible to incorporate additional desulfurization substances into the ladle, which improves the quality of the steel and makes it cheaper.

The release of the thermally pretreated manganese-containing oxide material on the surface of the metal melt in the ladle impairs the process of manganese reduction and the desulphurisation of the metal melt, as a result of which the quality of the finished steel deteriorates and the cost price increases.

Omitting the heating of the metal melt in the course of feeding the thermally pretreated manganese-containing oxide material into a stream of the neutral gas impairs the quality of the steel. This is due to the fact that the supply of cold substances in the bulk of the metal melt cools the metal melt, decreases the melting rate of the thermally pretreated manganese-containing oxide material, thereby deteriorating the conditions of the manganese reduction and the desulfurization degree of the metal melt is reduced. Moreover, a further supply of desulfurizing substances is made impossible due to a strict thermal regime of the steel preparation. All this detracts from the quality of the steel and makes the steel more expensive.

As the desulfurizing substance, a slag forming mixture is used, which is fed to the ladle in an amount selected in the ratio of the slag forming mixture to the reducing agent, fed in the first part, equal to successively (1.0-1.1) : (0.20-0.30).

Simultaneous addition of the desulfurizing mixture with the first part of the reducing agent ensures deoxidation and desulfurization of the carbonaceous semi-product even at the beginning of its transfer to the ladle. In addition, the slags formed on the surface of the metal melt have a high sulfide capacity. This favors the degree of desulphurization of the metal melt during the entire process of pouring the carbonaceous semi-finished product into the ladle. The reductant losses decrease in this case because the slags formed on the surface of the metal melt protect it from secondary oxidation and prevent the reductant from appearing on the surface of the molten and interacting with atmospheric oxygen.

The selected ratio of the desulfurizing slag mixture to the reducing agent equal to (1.0-1.1) :( 0.20-0.30) provides for the preparation in the ladle of a deoxidized metal melt with a low sulfur content and of covering slag with a high sulphide capacity. Decreasing the consumption of the desulfurizing mixture below the predetermined value decreases the desulfurizing capacity of the molten slag, that is, the sulfide capacity, which degrades the quality of the steel and increases its cost.

An increase in the consumption of the desulfurizing mixture also detracts from the quality of the steel because the slags formed on the surface of the metal melt have an increased viscosity. This leads to a deterioration of the kinetic conditions of the desulfurization of a metal melt. Reducing the consumption of the reducing agent to below a predetermined value degrades the deoxidation of the steel, leading to poor steel quality. The consumption of the reducing agent, which exceeds the predetermined value, leads to an uneconomical use of the reducing agent and degrades the quality of the steel due to the increased content of non-metallic inclusions in the steel. The release of another portion of the reducing agent is accompanied by the simultaneous addition of a further amount of desulfurizing agents.

As the desulfurizing agent, dolomite is used in a selected amount in the ratio of dolomite to reducing agent in the second portion equal to 0.8-1.2.

The above-described release of the substances into the ladle ensures economical use of the reducing agent because the dolomite, after melting, forms a protective slag layer on the surface of the metal melt, which protects the metal melt from secondary oxidation. The molten slag thus formed has a high sulfide capacity, which allows desulphurisation of the metal melt, thereby ensuring an improvement in the quality of the steel and a reduction in its cost price. A separate supply of the reducing agent and dolomite impairs the deoxidation process and the desulfurization of the metal melt. This occurs in connection with the fact that when the reducing agent is first introduced into the ladle, the reducing agent losses increase due to the interaction with atmospheric oxygen, the amount of non-metallic inclusions in the steel increases and the quality of the steel deteriorates. A prior supply of dolomite leads to thickening of the molten slag, which reduces the sulfide capacity and degrades the quality of the steel due to the increased sulfur content. The reducing agent is not used economically in this case and its losses due to interaction with atmospheric oxygen increase. The cost of the steel is rising.

In another example of the practice of the present invention, calcium carbide is used as a desulfurizing agent, wherein a first portion of the calcium carbide is released simultaneously with the first portion of the aluminum-containing material and lime in a selected amount in the ratio of lime to aluminum in the aluminum-containing material, respectively calcium carbide equal to (4.0-5.0) :( 0.3-0.6) :( 1.5-2.0) and the second part of the calcium carbide is further added with the second portion of the aluminum-containing material in a selected amount in the ratio of aluminum in the aluminum-containing material to calcium carbide successively (1.0-1.2) :( 2.5-3.6).

The release of the first part of the calcium carbide flush with lime and aluminum-containing material ensures intensive deoxidation and desulfurization of the carbonaceous semi-product, the formation of slags with a high sulfide capacity on the surface of the metal melt and economical use of all materials. This is due to the fact that the molten slag, which forms as a result of the melting of lime and calcium carbide, protects the metal melt from secondary oxidation with atmospheric oxygen, resulting in a low content of non-metallic oxide inclusions in course of deoxidation of the metal melt. A strong and complete deoxidation of the carbonaceous semi-product in the metal melt, almost completely isolated from interaction with atmospheric oxygen, gives rise to favorable desulfurization conditions.

The melting of the calcium carbide is therefore accompanied by a desulfurization of the metal melt.

The incorporation of lime into the ladle together with calcium carbide and aluminum-containing materials contributes to the formation of slags with a high sulfide capacity on the surface of the metal melt. All this makes it possible to prepare a high-quality sample and to lower its cost price.

An increase in calcium carbide consumption gives rise to a thickening of the molten slag, resulting in a reduction in sulfide capacity, increased reductant losses due to interaction with atmospheric oxygen, deterioration of desulfurization conditions and an increase in the content of non-sulfur -Metal inclusions in the steel. The quality of the finished steel thus deteriorates and the cost price increases.

Reducing the consumption of calcium carbide impairs the process of desulphurisation of the metal melt and gives rise to slags with a low sulfide capacity, thereby deteriorating the quality of the steel.

An increased use of the aluminum-containing material leads to an uneconomical use of this material and makes the finished steel more expensive. Reduced consumption of the aluminum-containing material detracts from the deoxidation and desulfurization of the steel and degrades its quality.

An increase in the consumption of lime gives rise to a thickening of the slag, reduces its sulfide capacity and detracts from the deoxidation and desulfurization of the metal melt due to the increased losses of the aluminum-containing material caused by its interaction with atmospheric oxygen. In addition, the amount of non-metallic inclusions in the steel increases. The quality of the finished steel therefore deteriorates and its cost price increases.

A reduction in lime consumption increases combustion of the aluminum-containing material due to its interaction with atmospheric oxygen. This increases the content of non-metallic inclusions in the steel, reduces the degree of desulphurisation and thus detracts from the quality of the finished steel and increases its cost price.

A further release of the second portion of the calcium carbide together with heat-treated oxide materials and with the second portion of the aluminum-containing material in an amount selected in the ratio of aluminum in the aluminum-containing material to calcium carbide successively equal to (1.0-1, 2) :( 2.5 ~ 3 »6) ensures the simultaneous deoxidation of a fresh part of the carbonaceous semi-product, its desulfurization and the reduction of alloying elements in the molten slag. This may be due to the fact that the reducing agent, namely the aluminum-containing material, which is introduced into the ladle, is protected by coating slag from oxidation with atmospheric oxygen and reacts readily with oxygen dissolved in the carbonaceous semi-product, and with oxygen, which is present in the oxides of the alloying elements in the slag.

Thus, favorable conditions are provided for the desulfurization of the metal melt with molten calcium carbide, which increases the sulfide capacity of the slag by binding acid oxides to complexes. As a result, the quality of the steel is improved and the cost price is reduced.

In the case of the separate delivery of the materials, the requirements of the above-described method are violated, the quality of the steel deteriorates and the cost increases.

When thermally pretreated oxide materials containing the alloying elements are first released, intensive melting takes place and the liquid slag is diluted. The content of oxides in the molten slag, which is the so-called "active oxygen", which is thermodynamically unstable oxides (in this case the oxides, which contain the alloying elements) is increasing. There is a redistribution of oxygen among the slag and the metal melt occurs and the oxygen concentration in the metal melt increases, which leads to a deterioration of the conditions for desulphurisation of the metal melt and to a deterioration of the quality of the finished steel, in addition to the conditions for the reduction of the alloying elements the melted slag deteriorates and the quality of the finished steel becomes poor.

The incorporation of thermally pretreated oxide materials containing the alloying elements after the release of the second portion of the calcium carbide and the reducing agent is also ineffective because an increased consumption of the reducing agent primarily intended to reduce the alloying elements from the molten slag gives rise to large losses of the reducing agent. An excess of the reducing agent emerges on the surface of the molten slag and interacts with atmospheric oxygen. All this reduces the quality of the steel and makes the steel more expensive.

The consumption of calcium carbide above the claimed ratio leads to a thickening of the molten slag, a reduction in its sulfide capacity and in the degree of desulfurization of the steel. In addition, the high viscosity of the molten slag makes the reduction of the alloying elements difficult. All this makes the quality of the steel worse and makes it more expensive.

The consumption of calcium carbide in the second portion of less than the claimed ratio detracts from the desulfurization conditions of the metal melt due to the reduced sulfide capacity of the slag. The quality of the steel deteriorates and the cost price increases.

The consumption of the reducing agent above the claimed ratio gives rise to an uneconomical use of the reducing agent, combustion of the reducing agent, contamination of the steel with non-metallic inclusions and thus poor quality and increased cost of the finished steel.

Consumption of the reducing agent below the claimed ratio favors the residual oxygen content in the steel, which is present in the form of non-metallic inclusions during hardening.

In addition, the degree of extraction of the alloying element from the molten slag decreases and the chemical composition of the finished steel may differ from the intended one. As a result, the desulfurization conditions of the metal melt deteriorate, the quality of it deteriorates and the cost increases.

Thus, if thermally pretreated materials, reducing agents, desulphurizing agents, and slag-forming materials are used in the above ratio and delivered into the ladle according to the described procedure, the proposed general purpose steel making process thus allows to improve the quality of the steel. improve by reducing the sulfur and non-metallic inclusions content and reducing their cost.

For a better understanding of the present invention, specific examples for the practice are given below by way of illustration.

For comparison, an example is given of the implementation of the method for preparing steel according to the known technology (SU-A-1,044,641) (example N 26).

The chemical composition and properties of the finished steel are shown in the Table.

Example I

The process for preparing a chromium-containing steel was carried out in a ladle with a capacity of 350 tons. A carbonaceous semi-product at a temperature of 1650 ° C was poured from an oxygen converter blown from above. The steel ladle was lined with a refractory material with a high silica content.

As an oxide material, a chromium-containing material was used which had been pretreated thermally at 1600 ° C with the following chemical composition (mass #): Cr 2 O - 70.8l, FeO - 12.20, Al 2 - 9.31, SiO 2 - 5, 94, MgO - 1.74.

As desulfurizing agents, a mixture of liquid flask containing not less than 75.0 mass # CaF2 (other secondary impurities - the rest) and freshly calcined lime, which (in mass #) CaO - 92.0 and MgO - 6 was used , 5 (other side impurities - the rest).

As the reducing agent, an aluminum-containing material was used: an aluminum alloy with an aluminum content of about 86 # (residual impurities), which was released simultaneously with the desulfurizing substances.

The first portion of the aluminum-containing material and the desulfurizing substance was released into the ladle simultaneously with the transfer therein of 1/3 of the mass of the carbonaceous semi-product (1 ton). Then, a chromium-containing oxide material was fed in an amount of 57 tons along with another portion of the aluminum-containing material in an amount of 1.8 tons, before transferring the carbonaceous semi-finished product into the ladle.

The finished steel was poured into a continuous casting machine (CCM) to make billets of 350 x 1650 mm, which were then rolled into 10-30 mm plates, and metallographic studies were performed.

The finished steel with the following chemical composition (mass #) was prepared: C - 0.12, Si - 0.25, Mn - 0.55, S - 0.004, P - 0.020, Al - 0.020, Cr - 0, 49, Ni - 0.70, Cu - 0.45, Fe - rest. The chrome extraction was 96.5 # *, the desulfurization rate was 71.4 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.6, sulfides - 1.8, silicates - 1.9.

The steel obtained was of high quality due to the low sulfur content and non-metallic inclusions.

Example II

The general purpose steel preparation process was carried out in a ladle while melting the carbonaceous semi-finished product in a 100 ton electric blast furnace.

Manganese-containing oxide material pretreated at 900 ° C, consisting of (in mass #) MnO + M ^ O ^ + MngO / y - 54.8 (Mn - 42.3), S1O2 - 18.0, Fe203 - 3, 0. CaO - 5.0, MgO - 2.1, C - 2.2, P - 0.5, S - 0.015, other side impurities - residue, was used as the oxide material containing the alloying element.

A lime and fluorspar based material as described in Example I was used for desulfurization and the same aluminum alloy as described in Example I was used as the metallic reducing agent for the reduction.

After preparing a semi-finished product in an electric blast furnace at 1640 ° C, it was poured over a six-minute period into a steel ladle fitted with an internal chamotte coating.

A first portion of the reducing agent in an amount of 60 kg along with the desulfurizing agent in an amount of 0.5 tons were released in the course of transferring 1/3 of the mass of the carbonaceous semi-product.

The second portion of the reducing agent in an amount of 0.565 tons along with 3.5 tons of the manganese-containing material was fed before completing the decanting of the carbonaceous semi-product.

Steel casting, rolling and metallographic studies were performed as described in Example I.

The finished steel had the following chemical composition, in mass #: C - 0.12, Si - 0.22, Mn - 1.51, S - 0.007, P - 0.011, Al - 0.022, Fe - residue.

The manganese extraction rate was 95.27 #; the desulfurization rate was 64.5 #

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.3, sulfides - 2.2, silicates - 1.7.

The finished steel was of high quality due to its low sulfur content and non-metallic inclusions.

Example III

The general purpose steel preparation process was carried out in a 100-ton ladle according to the procedure described in Example II.

The materials used and their amounts were the same as those in Example I.

The difference was that the oxide material containing the alloying element used a 1100 DEG C. heat-treated manganese oxide material having the same chemical composition as described in Example II.

Steel casting, rolling and metallographic studies were performed as described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.11, Si - 0.23, Mn - 1.53, S - 0.008, P - 0.010, Al - 0.023, Fe - residue.

The manganese extraction degree was 95.94% and the desulfurization degree 61.9 *.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.4, sulfides - 2.4, silicates - 1.8.

The finished steel was of high quality due to its low sulfur content and non-metallic inclusions.

Example IV

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedures described in Examples II and III.

The materials used and their amounts were the same as those described in Examples II and III.

The difference was that the oxide material containing the alloying element was a heat-treated manganese-containing oxide material of the same composition as described in Example II, treated at 1250 ° C.

The casting of the steel, its rolling and the metallographic investigations were carried out by following the procedures described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.12, Si - 0.23, Mn - 1.52, S - 0.007, P - 0.012, Al - 0.022, Fe - residue.

The manganese extraction degree was 94.49 # and the desulfurization degree 63.6 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.5. sulfides - 2.0, silicates - 1.9.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example V

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure described in Examples III-IV.

The materials used and their amounts were the same as those described in Example III. The difference was that the manganese-containing material was fed to the ladle in a jet of neutral gas (argon) and the metal melt was simultaneously heated by an electric arc.

The casting of the steel, its rolling and the metallographic investigations were carried out by following the procedures described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.12, Si - 0.21, Mn - 1.55, S - 0.004, P - 0.012, Al - 0.024, Fe - residue.

The manganese extraction degree was 97.9 # and the desulfurization degree 83.2 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.2, sulfides - 1.4, silicates - 1.6.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example VI

The general purpose steel preparation process was carried out in a ladle according to the procedure described in Example V.

The lime and fluorspar based material was used as a desulfurizing agent.

The difference was that the following materials were used as oxide materials containing the alloying elements: manganese-containing oxide material which had been thermally pretreated at 1100 ° C, similar to the material used in Example II; - Vanadium-containing oxide material, which was thermally pretreated at 1600 ° C, containing in mass #: V20tj - 85 (V - 47.77), Al2 O3-0.4, TiO - 1.8, SiO2 - 2.5, CaO - 2.1, Fe2 O3 - 7.0, MgO - 0.6, S - 0.3, P - 0.07, other side impurities - 0.23.

A metallic reducing agent, namely an aluminum-based alloy with the same chemical composition as the alloy described in Example I, was used as the reducing agent.

The semi-finished product was obtained in an electric blast furnace at 1645 * 0 and poured into a steel ladle with an internal chamotte coating in 6.5 min.

The first portion of the reducing agent (0.07 tons) along with the desulfurizing agent were released into the ladle in the course of transferring 1/3 of the mass of the carbonaceous semi-product therein. The mass of the desulfurizing substance in this case was 0.55 tons.

The second portion of the reducing agent was fed in a jet of neutral gas (argon) along with the oxide materials and the metal melt was simultaneously heated by an electric arc.

The mass of the reducing agent in this case was 0.63 tons, of the manganese-containing oxide material 3.5 tons, and of the vanadium-containing oxide material, 0.225 tons.

Steel casting, rolling and metallographic studies were performed as described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.10, Si - 0.22, Mn - 1.51, S - 0.004, P - 0.011, V - 0.10, Al - 0.022 , Fe - rest.

The extraction rates of manganese and vanadium were 93.7 and 94.2 #, respectively; the desulfurization rate was 79.2%.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.3, sulfides - 1.8, silicates - 1.8.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example VII

The general purpose steel preparation process was carried out in a 350-ton ladle according to the procedure described in Example I.

The same mixture as described in Example I was used as desulfurizing agent.

A manganese-containing oxide material which had been thermally treated at 1100 ° C with the same composition as that of Example II was used as the oxide material containing the alloying element.

For the reduction of the alloying element, a metallic reducing agent was used, namely an aluminum alloy. with the same composition as that in Example I.

The carbon-containing semi-product at 1650 ° C was poured from the converter over 6 min into the ladle equipped with an internal chamotte coating.

When the ladle was filled with 1/3 of the mass of the carbonaceous semi-finished product, the first part of the reducing agent and the desulfurizing agent were added in 0.46 and. 2.3 tons were placed in the ladle. Before completing the decanting of the carbonaceous semi-finished product, the second part of the reducing agent and the manganese-containing oxide material were added in amounts of 1.9 tons and 1. 12.6 tons issued.

The casting of the steel, its rolling and the metallographic investigations were carried out by following the procedures described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.09, Si - 0.62, Mn - 1.43, S - 0.005, P - 0.007, Al-0.027, Fe - residue. The manganese extraction rate was 95.9 #. the degree of desulfurization 61.2 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.4, sulfides - 1.8, silicates - 1.9.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example VIII

The general purpose steel preparation process was carried out in a 350-ton ladle by following the procedure described in Example VII.

The materials used and the amounts thereof were the same as those described in Example VII.

The difference was that the consumption of the reducing agent and the desulfurizing substance, which formed a slag-forming mixture, were put together all at once in the ladle.

In this example, the consumption of the slag-forming mixture was 2.3 tons and of the reducing agent 0.69 tons, that is, the ratio of the amount of the slag-forming mixture to that of the reducing agent in the first portion was 1.0 successively. : 0.3.

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example I.

The finished steel had the following chemical composition (by mass - /!): C - 0.10, Si - 0.60, Mn - 1.46, S - 0.004, P - 0.010, Al-0.033. Fe - rest.

The manganese extraction rate was 91.3%, the desulfurization degree - 58.4 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.5, sulfides - 1.9, silicates - 1.9.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example IX

The general purpose steel preparation process was carried out in a 350-ton ladle by following the procedure described in Example VII.

The materials used and the amounts thereof were the same as those in Example VII. The difference was in the consumables of the reducing agent and the desulfurizing agents which formed the slag-forming mixture and were placed in the ladle along with a first portion of the reducing agent. In this example, the consumption of the slag forming mixture was 2.5 tons and of the reducing agent 0.45 tons, that is, the ratio was 1.1: 0.2 successively.

The casting of the steel, its rolling and the metallographic investigations were carried out by following the procedures described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.10, Si - 0.63, Mn - 1.42, S - 0.005, P - 0.010, Al - 0.030, Fe - residue.

The manganese extraction degree was 95.6 #, the desulfurization degree - 55.9 # *

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.3, sulfides - 1.8, silicates - 1.8.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example X.

The general purpose steel preparation process was carried out in a 350-ton ladle by following the procedure described in Example VII.

The materials used and their amounts were the same as those in Example VII. The difference was in the consumption of the reducing agent and the desulfurizing agent, which was introduced into the ladle simultaneously with a first portion of the reducing agent. In this example, the consumption of the reducing agent was 0.47 tons and of the desulfurizing agent 1.72 tons, the ratio being 0.3: 1.1 successively.

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.11, Si - 0.54, Mn - 1.46, S - 0.006, P - 0.012, Al - 0.024, Fe - residue.

The manganese extraction rate was 93.7 #. the desulfurization degree 63.1 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.6, sulfides - 1.4, silicates - 1.7.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example XI

The general purpose steel preparation process was carried out in a 350-ton ladle by following the procedure described in Example VII.

The materials used and their amounts were the same as those described in Example VII. The difference was in the consumption of the reducing agent and the desulfurizing agent, which was introduced into the ladle simultaneously with a first portion of the reducing agent. In this example, the consumption of the desulfurizing agent was 1.95 tons and the reducing agent was 0.46 tons, i.e. its ratio was 1.05: 0.25.

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.12, Si - 0.57, Mn - 1.49, S - 0.004, P - 0.011, Al - 0.034, Fe - residue.

The manganese extraction rate was 96.7 # »the desulfurization degree 64.9 #

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.4, sulfides - 1.3, silicates - 1.6.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example XII

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure in Example VI.

The same materials were used. The difference lies in the consumption of the manganese-containing oxide material, which in this example was 1.2 tons.

In addition, in this example, the desulfurizing agent was also added to the ladle at the same time as the second portion of the reducing agent and the manganese-containing oxide material, the consumption of the desulfurizing agent being equal to that used in Example I and the consumption 0. .05 tons; the consumption of the second part of the reducing agent was 0.2 tons.

The casting of the finished steel, its rolling and the metallographic investigations were performed in the same manner as described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.10, Si - 0.24, Mn - 1.51, S - 0.004, P - 0.012, Al - 0.031, Fe - residue.

The manganese extraction degree was 93.8 #, the desulfurization degree 82.4 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.7, sulfides - 1.4, silicates - 1.6.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example XIII

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure described in Example XII.

The materials used and the amounts thereof were the same as those reported in Example XII.

The difference was in the composition of the desulfurizing agent, which was also placed in the ladle along with the second portion of the reducing agent. In this example, the desulfurizing substance consisted of 70 # CaO, 10 # CaF2 and 20 # AI2O3, while the consumption of this substance was 0.5 tons.

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.12, Si - 0.21, Mn - 0.49, S - 0.006, P - 0.010, Al - 0.026, Fe - residue.

The manganese extraction degree was 94.4 #, the desulfurization degree 74.9 #

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.8, sulfides - 1.9, silicates - 2.1.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example XIV

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure described in Example XII.

The same materials used in the same amounts were used. The difference lies in the consumption of the desulfurizing substance, which is also placed in the ladle together with the second part of the reducing agent.

In this example, the desulfurizing substance consisted of 60 # CaO, 10 # MgO, 5 # CaF £ and 25 # Al2O3, while the consumption of this substance was 0.5 tons.

Steel casting, rolling and metallographic studies were performed as described in Example I.

The finished steel had the following composition (in mass #): C-0.10, Si - 0.28, Mn - 0.50, S - 0.006, P - 0.012, Al - 0.028, Fe residue.

The manganese extraction degree was 85 * 6 #, the desulfurization degree 71.4 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.9, sulfides - 1.8, silicates - 2.0.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example XV

The general purpose steel preparation process was carried out in a 350-ton ladle by following the procedure described in Example XI.

The same materials used in the same amount were used.

The difference was that dolomite as desulfurizing agent was also supplied to the ladle along with a further amount of reducing agent and manganese oxide material, the dolomite consumption being chosen in proportion to the second portion of the reducing agent equal to 0.8 . Dolomite consumption was 1.75 tons.

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.09, Si - 0.57, Mn - 1.48, S - 0.005, P - 0.012, Al - 0.020, Fe - residue. The manganese extraction degree was 93.7%, the desulfurization degree was 79.4%.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.7, sulfides - 1.5, silicates - 1.9-

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example XVI

The general purpose steel preparation process was carried out in a 350-ton ladle by following the procedure described in Example XV. The same materials in the same amounts were used. The difference was in the consumption of dolomite, which was supplied to the ladle with the second part of the reducing agent. In this example, the dolomite consumption was selected in its ratio to the amount of the reducing agent in the second portion of 1.0. The dolomite consumption was 2.2 tons.

The casting of the steel, its rolling and the metallographic investigations were performed as described in Example XV.

The finished steel had the following chemical composition (in mass #): C - 0.12, Si - 0.51, S - 0.006, P - 0.015, Al - 0.027, Fe residue.

The manganese extraction degree was 96.1 #, the desulfurization degree 74.6 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.7, sulfides - 1.9, silicates - 1.5 -

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example XVII

The general purpose steel preparation process was carried out in a 350-ton ladle by following the procedure described in Example XV. The same materials in the same amounts were used. The difference was in the consumption of dolomite, which was delivered into the ladle with the second part of the reducing agent. In this case, the consumption of dolomite was chosen in the ratio of dolomite to the second part of the reducing agent of 1.2. Dolomite consumption was 2.6 tons.

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.010, Si - 0.56, Mn - 1.46, S - 0.005, P - 0.012, Al - 0.021, Fe - residue.

The manganese extraction degree was 83.8 #, the desulfurization degree 76.8 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.5, sulfides - 1.4, silicates - 1.8.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example XVIII

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure described in Example I.

The same materials in the same amounts were used. The difference was that in this case calcium carbide was used as a desulfurizing agent which was released with the first part of the aluminum-containing material and also with the second part of the aluminum-containing material. The calcium carbide, which was introduced into the ladle with the first part of the aluminum-containing material, was released together with lime, the lime being used in an amount selected in the ratio of lime to aluminum in the aluminum-containing material and until the calcium carbide was equal to successively 4.0: 0.3: 1.5-

The total amount of lime, aluminum-containing material and calcium carbide was 0.6 tons.

The amount of calcium carbide introduced into the ladle with the second portion of the aluminum-containing material was selected in the ratio of aluminum in the aluminum-containing material to the calcium carbide of 1: 2.5 successively. Calcium carbide consumption was 0.3 tons. .

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example I.

The finished steel had the following chemical composition (by mass - /!): C - 0.10, Si - 0.21, Mn - 0.52, S - 0.004, P - 0.014, Al-0.023, Fe - residue .

The manganese extraction degree was 94.7 #, the desulfurization degree 79.1 #

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.5 sulfides - 1.2, silicates - 1.8.

The finished steel was of excellent quality due to its low sulfur content and non-metallic inclusions.

Example XIX

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure described in Example XVIII.

The same materials in the same amounts were used. The difference lay in the consumption of calcium carbide. The amount of calcium carbide released into the ladle along with the first portion of the aluminum-containing material and lime was selected in the ratio of lime to aluminum in the aluminum-containing material and to calcium carbide successively 4.0: 0.6: 1, 5.

The total amount of lime, aluminum-containing material and calcium carbide was 0.6 tons.

The amount of calcium carbide released into the ladle with the second portion of the aluminum-containing material was selected in the ratio of aluminum in the aluminum-containing material to calcium carbide successively 1: 3.6, while the calcium carbide consumption was 0.55 tons.

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.12, Si - 0.24, Mn - 0.49, S - 0.006, P - 0.019, Al - 0.024, Fe - residue.

The manganese extraction degree was 92.3 # · the desulfurization degree 76.8 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.8, sulfides - 1.9, silicates - 2.0.

The finished steel was of excellent quality thanks to a low sulfur content and non-metallic inclusions.

Example XX

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure described in Example XVIII.

The same materials in the same amounts were used. The difference lay in the consumption of calcium carbide. The amount of calcium carbide released into the ladle along with the first portion of the aluminum-containing material and the lime was selected in the ratio of lime to aluminum in the aluminum-containing material and to the calcium carbide successively 4.0: 0.5: 2 , 0.

The total amount of lime, aluminum-containing material and calcium carbide was 0.6 tons.

The amount of calcium carbide released into the ladle with the second portion of the aluminum-containing material was selected in the ratio of aluminum in the aluminum-containing material to calcium carbide successively 1: 3 * 0, while the consumption of the calcium carbide was 0.45 tons .

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.09, Si - 0.21, Mn - 0.52, S - 0.005, P - 0.016, Al - 0.021, Fe - residue.

The manganese extraction degree was 96.3 #, the desulfurization degree 79.8 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.6, sulfides - 1.7, silicates - 1.9 *

The finished steel was of excellent quality thanks to a low sulfur content and non-metallic inclusions.

Example XXI

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure described in Example XVIII.

The same materials used in the same amounts were used. The difference lay in the consumption of calcium carbide. The amount of calcium carbide released into the ladle along with the first portion of the aluminum-containing material and the lime was selected in the ratio of lime to aluminum in the aluminum-containing material and the calcium carbide successively 4.0: 0.5: 1 The total amount of lime, aluminum-containing material and calcium carbide was 0.6 tons.

The amount of calcium carbide incorporated into the ladle simultaneously with the second portion of the aluminum-containing material was selected in the ratio of aluminum in the aluminum-containing material to calcium carbide successively 1.2: 2.5. Calcium carbide consumption was 0.35 tons.

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example XVIII.

The finished steel had the following chemical composition (in mass #): C - 0.10, Si - 0.25, Mn - 0.54, S - 0.006, P - 0.018, Al - 0.023, Fe - residue.

The manganese extraction degree was 97.IJ., the desulfurization degree 74.9 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.7, sulfides - 1.9, silicates - 1.6.

The finished steel was of excellent quality thanks to a low sulfur content and non-metallic inclusions.

Example XXII

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure described in Example XVIII.

The same materials used in the same amounts were used. The difference lay in the consumption of calcium carbide. The amount of calcium carbide released into the ladle along with the first portion of the aluminum-containing material and the lime was selected in the ratio of lime to aluminum in the aluminum-containing material and calcium carbide of successively 5.0: 0.3: 1, 5- The total amount of lime, aluminum-containing material and calcium carbide was 0.6 tons.

The amount of calcium carbide introduced into the ladle along with the second portion of the aluminum-containing material was selected in the ratio of aluminum in the aluminum-containing material to calcium successively 1.2: 3.6.

Calcium carbide consumption was 1.08 tons.

Casting of the finished steel, rolling it and metallographic investigations were performed as described in

Example XVIII.

The finished steel had the following chemical composition (in mass #): C - 0.11, Si - 0.23, Mn - 0.51, S - 0.004, P - 0.021, Al - 0.025, Fe - residue.

The manganese extraction degree was 95.3 #, the desulfurization degree 79.8 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.6, sulfides - 1.4, silicates - 1.8.

The finished steel was of excellent quality thanks to a low sulfur content and non-metallic inclusions.

Example XXIII

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure described in Example XVIII.

The same materials used in the same amount were used. The difference lay in the consumption of calcium carbide. The amount of calcium carbide released into the ladle together with the first portion of the aluminum-containing material and the lime was selected in the ratio of lime to aluminum in the aluminum-containing material and to calcium carbide of successively 5.0: 0.6: 1, 5- The total amount of lime, aluminum-containing material and calcium carbide was 0.6 tons.

The amount of calcium carbide introduced into the ladle along with the second portion of the aluminum-containing material was selected in the ratio of aluminum in the aluminum-containing material to the calcium carbide successively 1.2: 3.0. The consumption of the calcium carbide was 0.4 tons.

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example XXII.

The finished steel had the following chemical composition (in mass #): C - 0.12, Si - 0.27, Mn - 0.55, S - 0.005, P - 0.014, Al - 0.026, Fe - residue.

The manganese extraction degree was 97.6 #, the desulfurization degree 77.4 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.5, sulfides - 1.7, silicates - 2.0.

The finished steel was of excellent quality thanks to a low sulfur content and non-metallic inclusions.

Example XXIV

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure described in Example XVIII.

The same materials used in the same amount were used. The difference lay in the consumption of calcium carbide.

The amount of calcium carbide released into the ladle along with the first portion of the aluminum-containing material and the lime was selected in the ratio of lime to aluminum in the aluminum-containing material and the calcium carbide of successively 5.0: 0.5 : 2.0. The total amount of lime, aluminum-containing material and calcium carbide was 0.6 tons.

The amount of calcium carbide incorporated into the ladle along with the second portion of the aluminum-containing material was selected in the ratio of aluminum in the aluminum-containing material to the calcium carbide successively 1.1: 3.0. The consumption of the calcium carbide was 0.45 tons.

The casting of the finished steel, its rolling and the metallographic investigations were performed as described in Example XXII.

The finished steel had the following chemical composition (in mass #): C - 0.09, Si - 0.21, Mn - 0.52, S - 0.004, P - 0.017, Al-0.023, Fe - residue.

The manganese extraction degree was 94.1 #, the desulfurization degree 81.2 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.5, sulfides - 1.2, silicates - 1.7.

The finished steel was of excellent quality thanks to a low sulfur content and non-metallic inclusions.

Example XXV

The general purpose steel preparation process was carried out in a 100-ton ladle by following the procedure described in Example XVIII.

The same materials used in the same amount were used. The difference lay in the consumption of calcium carbide. The amount of calcium carbide released into the ladle along with the first portion of the aluminum-containing material and the lime was selected in the ratio of lime to aluminum in the aluminum-containing material and the calcium carbide of successively 5.0: 0.5 : 1.7- The total amount of lime, aluminum-containing material and calcium carbide was 0.6 tons.

The amount of calcium carbide introduced into the ladle along with the second portion of the aluminum-containing material was the same as in Example XXIV and was 0.45 tons.

Casting of the finished steel, rolling it and metallographic investigations were performed as described in

Example XVIII.

The finished steel had the following chemical composition (in mass #): C - 0.12, Si - 0.22, Mn - 0.50, S - 0.005, P - 0.014, Al - 0.020, Fe - residue.

The manganese extraction rate was 93.9 #. the degree of desulfurization 77.3 #

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 1.7, sulfides - 1.4, silicates-1.9-

The finished steel was of excellent quality thanks to a low sulfur content and non-metallic inclusions.

Example XXVI (comparison)

A general purpose steel was treated in a 350 ton ladle according to known technology (SU-A-1.044.64l).

After pouring the total amount of the carbonaceous semi-finished product into the ladle, 4.2 tons of manganese slag from the low phosphorus ferroalloy preparation were prepared with the following chemical composition (by mass #): S1O2 - 25, MnO - 65 , CaO - 5.5 * FeO - 0.2, Al2O3 -2.2, Mg 0-2.3, P - 0.010, other side impurities residue; 3.3 tons of lime, which contained 60 # CaO, and 0.72 tons of aluminum-containing material, consisting of 86 # aluminum and other contaminants (the rest) were placed in the ladle.

Oxygen was then added to the surface of the melt for 15 seconds, after which the metal melt was blown with argon for 10 minutes.

The casting of the finished steel, its rolling and the metallographic studies were performed as described in Example I.

The finished steel had the following chemical composition (in mass #): C - 0.12, Si - 0.24, Mn - 0.50, S - 0.018, P - 0.020,

Al - 0.021, Fe - rest.

The manganese extraction degree was 70.4 #, the desulfurization degree 21.2 #.

The contamination of the steel with non-metallic inclusions (in points) was as follows: oxides - 3.2, sulfides - 3.6, silicas - 2.9

The finished steel was of poor quality due to a high sulfur content and non-metallic inclusions.

Table

Pre-chemical composition of the finished steel, mass image _ C Si Mn SP Al V Cr Fe 123 ^ 5 6 789 10 I 0.12 0.25 0.55 0.004 0.020 0.020 - 0.49 residue II 0.12 0.22 1.51 0.007 0.011 0.022 - in 0.11 0.23 1.53 0.008 0.010 0.023 - IV 0.12 0.23 1.52 0.007 0.012 0.022 - - V 0.12 0.21 1.55 0.004 0.012 0.024 - - VI 0.10 0.22 1.51 0.004 0.011 0.022 - - VII 0.09 0.62 1.43 0.005 0.007 0.027 - - VIII 0.10 0.60 1.46 0.004 0.010 0.033 - IX 0 , 10 0.63 1.42 0.005 0.010 0.030 - - X 0.11 0.54 1.46 0.006 0.012 0.024 - - XI 0.12 0.57 1.49 0.004 0.011 0.034 - XII 0.10 0.24 0 .51 0.004 0.012 0.031 - XIII 0.12 0.21 0.49 0.006 0.010 0.026 - XIV 0.10 0.28 0.50 0.006 0.012 0.028 - XV 0.09 0.57 1.48 0.005 0.012 0.020 - XVI 0 , 12 0.51 1.51 0.006 0.015 0.027 - XVII 0.10 0.56 1.46 0.005 0.012 0.021 - XVIII 0.10 0.21 0.52 0.004 0.014 0.023 --- XIX 0.12 0.24 0 .49 0.006 0.019 0.024 - XX 0.09 0.21 0.52 0.005 0.016 0.021 - XXI 0.10 0.25 0.54 0.006 0.018 0.023 - XXII 0.11 0.23 0.51 0.04 0.021 0.025. ..

XXIII 0.12 0.27 0.55 0.005 0.014 0.026 - XXIV 0.09 0.21 0.52 0.004 0.017 0.023 - XXV 0.12 0.22 0.50 0.005 0.014 0.020 - XXVI 0.12 0.24 0 50 0.018 0.020 0.021 -

Table (continued)

Desulfurization Manganese Contamination with non-metallic image grade,% extraction inclusions, grade,% average maximum points_

Oxides Sulphides Silicates 1 11 12 13 14 15 I 71.4 96.3 1.6 1.8 1.9 II 64.5 95.27 1.3 2.2 1.7 III 61.9 95.94 1, 4 2.4 1.8 IV 63.6 94.49 1.5 2.0 1.9 V 83.2 97.9 1.3 1.4 1.6 VI 79.2 93.7 1.3 1 .8 1.8 VII 61.2 95.9 1.4 1.8 1.9 VIII 58.4 97.9 1.5 1.9 1.9 IX 55.9 95.6 1.3 1.8 1.8 X 63.1 93.7 1.6 1.4 1.7 XI 64.9 96.7 1.4 1.3 1.6 XII 82.4 93.8 1.7 1.4 1, 6 xiii 74.9 94.4 1.8 1.9 2.1 XIV 71.4 95.6 1.9 1.8 2.0 XV 79.4 93.7 1.7 1.5 1.9 XVI 74.6 96.1 1.7 1.9 1.5 XVII 76.8 93.9 1.5 1.4 1.8 XVIII 79.1 94.7 1.5 1.2 1.8 XIX 76, 8 92.3 1.8 1.9 2.0 xx 79.8 96.3 1.6 1.7 1.9 XXI 74.9 97.1 1.7 1.9 1.6 XXII 79.8 95 , 3 1.6 1.4 1.8 XXIII 77.4 97.6 1.5 1.7 2.0 XXIV 81.2 94.1 1.5 1.2 1.7 xxv 77.3 93.9 1.7 1.4 1.9 xxvi 21.2 70.4 3.2 3.6 2.9

As can be seen from the above Examples and the Table, the degree of desulfurization, the manganese extraction degree are increased many times, and the contamination of the steel with non-metallic inclusions is significantly reduced by using the proposed invention. At the same time, the preparation of a general purpose steel is cheap.

Industrial applicability

The present invention can be used in the preparation of general purpose converter, Siemens-Martin and electric steel.

The present invention is most effectively used in the preparation of a manganese-containing steel in a ladle.

Claims (8)

A method of preparing a general purpose steel consisting of melting a carbonaceous semi-finished product in a steel making complex, transferring the semi-finished product into a ladle, dispensing desulfurizing agents, a reducing agent and heat-treated oxide materials into the ladle, containing alloying elements, characterized in that the reducing agent is supplied in portions to the ladle, the first portion being supplied together with the above-mentioned desulfurizing substances in the course of pouring not more than a third of the mass of the carbonaceous semi-finished product , and the second portion is fed together with thermally pretreated oxide materials before transferring the carbonaceous semi-finished product into the ladle. A method of preparing a general purpose steel consisting of melting a carbonaceous semi-finished product in a steel-making complex, pouring the semi-finished product into a ladle, dispensing desulfurizing agents into the ladle, a reducing agent and heat-treated oxide materials containing alloying elements, characterized in that the reducing agent is introduced into the ladle in sections, the first section being fed in together with the above-mentioned desulfurizing substances in the course of pouring not more than a third of the mass of the carbon -dend semis, and the second portion is fed along with heat-treated oxide materials before completing the pouring of the carbonaceous semis into the ladle. A method according to claim 1, characterized in that manganese-containing materials which have been thermally pretreated at 900-1250 ° C are used as the aforementioned thermally pretreated oxide materials. A method according to claim 1, characterized in that manganese-containing materials which have been thermally pretreated at 900-1250 ° C are used as the aforementioned thermally pretreated oxide materials. A method according to claim 2, characterized in that the aforementioned thermally pretreated manganese-containing oxide materials are delivered into the ladle in a stream of neutral gas, while the metal melt is heated simultaneously. A method according to claim 2, characterized in that the aforementioned thermally pretreated manganese-containing oxide materials are delivered into the ladle in a neutral gas stream, while the metal melt is simultaneously heated. The method according to claim 1, characterized in that a slag-forming mixture is used as the above-mentioned desulfurizing substance, which is delivered into the ladle in an amount selected in a ratio of the mixture to the reducing agent which is used in the first part. fed successively (1.0-1.1): (0.2-0.3). The method according to claim 1, characterized in that a slag-forming mixture is used as the above-mentioned desulfurizing substance, which is delivered into the ladle in an amount selected in a ratio of the mixture to the reducing agent which is added with the first part. fed successively (1.0-1.1): (0.2-0.3). Method according to claim 1, characterized in that the release of the second part of the reducing agent is accompanied by a simultaneous further supply of desulfurizing substances. Method according to claim 1, characterized in that the release of the second part of the reducing agent is accompanied by a simultaneous further supply of desulfurizing substances. 6. A method according to claim 5, characterized in that dolomite is used as the above-mentioned desulfurizing substance, which is also delivered into the ladle together with the second part of the reducing agent, the amount of dolomite being chosen in a ratio of dolomite to the reducing agent, fed simultaneously with the dolomite, from 0.8-1.2. A method according to claim 5, characterized in that dolomite is used as the above-mentioned desulfurizing substance, which is further released into the ladle together with the second part of the reducing agent, the amount of dolomite being selected in a ratio of dolomite to the reducing agent, fed simultaneously with the dolomite, from 0.8-1.2. Method according to claim 1 or 4 or 6, characterized in that an aluminum-containing material is used as the reducing agent. Method according to claim 1 or 4 or 6, characterized in that an aluminum-containing material is used as the reducing agent. 8. A method according to claim 5, characterized in that an aluminum-containing material is used as the reducing agent. 9. Process according to claims 1, 5 and 7, characterized in that calcium carbide is used as the desulfurizing substance, which is released together with the first part of the aluminum-containing material and is supplied simultaneously with lime, used in the amount selected in a ratio of lime to aluminum in the aluminum-containing material and to calcium carbide successively (^ »0-5.0) :( 0.3-0.6) :( 1.5-2.0), while the calcium carbide, which is further with the second portion of the aluminum-containing material being added, dispensed in an amount selected in a ratio of aluminum in the aluminum-containing material to calcium carbide successively (1.0-1.2) :( 2.5-3.0). II Conclusions (as amended during the international phase) Process according to claim 1, characterized in that calcium carbide is used as the desulfurizing substance, which is released together with the first part of the aluminum-containing material and is simultaneously supplied with lime in an amount selected in a ratio of lime to aluminum in the aluminum-containing material and up to the calcium carbide successively (4.0-5.0) :( 0.3-0.6) :( 1.5-2.0), while the calcium carbide, which is also the second portion of the aluminum-containing material is supplied, dispensed in an amount selected in a ratio of aluminum in the aluminum-containing material to calcium carbide in succession (1.0-1.2) :( 2.5 "3.0).