SU1002367A1 - Exothermic mixture - Google Patents

Description

The goal is achieved by the fact that an exotic atm mixture, including a reducing agent, sodium nitrate, plate sph, silica, lime and oxide of the alloying element, contains the components in the following ratio, wt.%: Reducing agent 16-20 Sodium nitrate 5-15 Lime5-8 Spar spar 0.1-5.0 Oxide of alloying element .26-40 Silica20-40 The ratio of calcium oxides to silicon oxides is (0.2 O, 4: 1.) With a mixture basicity in the range of 0.2-0.40, the degree of extraction the alloying element from its oxide is increased to 80-95%. This is explained by the fact that during the specimen the thermal reaction of the alumina obtained from the combustion of the reducing agent binds to the silicon oxides, thus the equilibrium of the reaction shifts towards the formation of the alloying element from its oxide. In addition, the low basicity of the slag because of the developed mixture reduces the oxygen content in steel. The lower the slag basicity, t more OH will remove oxygen from the metal, which in turn leads to a decrease in oxide and global inclusions in the metal. As a reducing agent, the exothermic mixture may contain aluminum powder or silicon-containing materials (silicocalcium, silicomanganese, etc.). The amount of the reducing agent in the composition of the mixture is selected on the basis of the exothermal reaction — 2700–3000 kJ / kg, which provides slag and ligature with a temperature of 1500 ° C. When the fuel content is below 16%, the degree of reduction of the doping element is reduced, and the slag-forming metal ligature has a low temperature. . Oxides of chromium, manganese, nickel or molybdenum can be used as the oxide of the doping element. The increase in fuel above 20% leads to a deterioration in the physicochemical properties of slag C (increased viscosity) due to an excessive concentration of silica oxides. Their content is determined by the amount of the alloying element, which must be introduced into the metal, depending on the grade of steel. Sodium nitrate is introduced in an amount that provides the required rate of burning of the mixture. Its amount should be substantially less than that required by stoichiometry for the complete oxidation of the reducing agent. When the content of nitrate is below 5%, the mixture does not burn, and its content is above 15%, does not allow to enter the required amount of the alloying element, since the proportion of oxide of this element in the mixture decreases. Fluorspar serves to reduce the ignition temperature of the mixture. The limits of its fluctuations in the composition of the mixture are due to the fact that when the content of spar is less than 0.1%, the ignition temperature is not regulated, and if it is higher than 5%, the sanitary and hygienic working conditions deteriorate. The amount of lime and silica in the composition of the mixture is chosen from the condition of obtaining a basicity of 0.2-0.4 to ensure the maximum degree of extraction of the alloying element and improve the refining properties of the slag. The lime content in the mixture is 5-8% due to the fact that within these limits the maximum degree of extraction of the alloying element is achieved. When the content of lime is less than 5%, the burning rate of the mixture is not necessary due to the increase in the density of the mixture, and an increase above 8% leads to an increase in the basicity of the slag and a decrease in the content in the mixture of oxides of the alloying element. When the silica content is less than 20%, the basicity of the slag increases by more than 0.4, which leads to a decrease in the degree of extraction of the alloying element from its oxide. An increase in silica of more than 40% leads to a decrease in the oxide content of the alloying element and a decrease in the amount of the alloying element introduced into the steel. With a basicity of 0.4 or less, the equilibrium of the reduction reaction of the alloying element from its oxide shifts towards the formation of the alloying element due to the binding of silica formed during the reaction of the oxide, and with an increase in basicity of more than 0.4, the reduction reaction slows down. By reducing the basicity of less than 0.2, the amount of the alloying element introduced into the metal decreases, since the reduction of the basicity is achieved by increasing the silica content and reducing the oxide of the alloying element. Mixtures are made in special compartments by mixing the components of the mixture in mixers. The mixture components are loaded in the following sequence: inert slag-forming materials, sodium nitrate, oxide of the alloying element, fluorspar and reducing agent. After a uniform transfer, the mixture is poured into a special container that is delivered to the workshop. Before discharging the metal from the furnace, the steel teeming ladle is filled. a mixture in the amount of 3-6% by weight of melting. The composition of the slag-metaplastic ligature, obtained after burning the mixture under the hood, provides for the introduction into the metal of the required amount of the alloy element and the refining of the metal from oxide inclusions. Then the ladle with a liquid slag-metal ligature is served under the release of smelting, where it is processed. Depending on the grade of steel being treated, the composition of the mixture as an oxide of the alloying element can include manganese, chromium, molybdenum and other concentrates.

Below are examples of mixtures and options for their use in the processing of low-alloy steel.

Ptr meper 1. The composition of the mixture, wt.%:

Aluminum powder 16 Sodium - saltpeter 11. Lime.8

Fluorspar - 5 Oxide of alloying

element 40 Silica20

Basicity mixture. 0.4 The use of a mixture of such a composition provides for the extraction of an alloying element from its oxide with 80%, and forming a slag metal ligature containing: wt.%: Calcium oxide 9; alumina. silica 2 calcium fluoride 6 (sodium oxide 5 manganese oxide 5 | - manganese 16; in mixture 1, it allows you to enter 1-1.5% manganese, depending on the consumption of the mixture, and reduce glomerular inclusions in steel to 1.5 points.

When machining 09G2 low carbon manganese steel, the manganese content increases from 0.4 to 1.4%, globular inclusions in steel will be 1.4 points.

PRI me R 2. The composition of the mixture, wt .-%: Silicocalcium 20

Sodium nitrate 15 Lime .5

Plavikrviy spar. OD Okiesel alloying

item 39.9.

Silica. 20 The basicity of the mixture of 0.25

As a result of burning the mixture, slag metal ligature of the next stage is obtained, wt.%: Calcium oxide 16 silica 54 calcium fluoride 2 sodium oxide 7 / manganese oxide 2.J manganese 19. When processing manganese crust, the mixture allows to introduce into the metal 1-2% manganese from a recovery rate of 95% and a reduction in globular inclusions in steel to 1 percent.

When processing manganese steel 20Г2, the manganese content increases from 0.2 to.

Steel contains globular inclusions of 1 point,

PRI me R 3. The composition of the mixture, wt.%:

Aluminum powder 16 Sodium nitrate 5 Lime.8

Fluorspar5

Oxide of alloying element26

Silica 40

The basicity of the mixture 0,2

A mixture of this composition will provide slag metal ligatures containing, wt.%: Calcium oxide 9, silica 34, cassia fluoride 6, sodium oxide 2, manganese oxide 2, alumina 35, manganese 12, with which it is possible to alloy steel with manganese to 1% and reduce the size of the globular inclusions to 1.3 b.

When processing this mixture of 09G2 steel, 1% manganese was introduced into the metal, and the content of globular inclusions was reduced to 1.3 points.

PRI me R 4. The composition of the mixture, wt.%:

Aluminum powder 18 Sodium nitrate 9.5 Lime6.5Plastic spar - 3 Oxide of alloying element33

Silica30

The basicity of the mixture 0,22

Slag metal ligature obtained by burning such a mixture has the following composition, wt%: calcium oxide 8, silica 29, alumina 36, calcium fluoride 3, sodium oxide 5, manganese oxide 4, manganese 15. When metal is processed in such a slag, the size is globular inclusions do not exceed 1.2 points, and the degree of extraction of the alloying element from its oxide reaches 93%.

After treatment with this mixture of 50G2 steel, the content of manganese increased by 1.5%, the content of globular inclusions was 1.2 bc.

Thus, the mixture allows to increase the degree of extraction of the alloying element up to 80-95% and reduce

content in steel of non-metallic inclusions up to 1-1.5 points.

Claims (2)

1. An exothermic mixture containing reducing agent, sodium nitrate, limestone, fluorspar, silica and oxide of the alloying element, characterized in that, in order to increase the degree of extraction of the alloying element and reduce steel and non-metallic inclusions, it contains components in the following ratio, weight .%: Reducing agent Sodium Nitrate Fluorspar Lime Doping oxide element Silica 2. The mixture of calcium oxides to silicon oxides according to claim 10, is (0.2-0.4) tl. Sources of information taken into account in the examination 1. Steel, 1977, 11, p. 13. 2, Japan Patent 51-8748, cl. 11 B 1, 1976.