SU1294836A1 - Slag-forming mixture for alloying steel - Google Patents

Abstract

The invention relates to ferrous metallurgy, in particular to the smelting of high alloy steels using slag-forming mixtures for vanadium doping. The aim of the invention is to reduce the loss of alloying elements and the loss of service properties of steel. The yak-forming mixture for steel alloying contains, wt%: vanadium, metal extractor 40-50; lime or lime to 35-45 and alumina 10-20. The degree of transition of vanadium and manganese to metal increases by 2.5-3.5%. Utility properties. steels increase by 10-15%. . ., 2 tab. S

Description

The invention relates to ferrous metallurgy, in particular, to methods for smelting high-alloyed steels using a slag-forming mixture for doping with vanadium.

The aim of the invention is to reduce the loss of alloying elements and improve the sponge properties of steel.

The proposed galaxy-forming mixture for alloying steel contains vanadium metal extractor, lime or limestone and alumina in the following ratio, wt.%

Vanadium Metal ™

screenings40-50

Lime or

known k35-45

Alumina10-20

Experiments carried out in npoNaimneHHUx-CONDITIONS} showed that using the proposed mixture to form slag melting period, calcareous homogeneous slags with reduced viscosity are obtained. This is achieved by reacting the aluminum oxides contained in the alumina with lime and the components of the primary slag ;; At the same time, a higher solubility is ensured. The known activity of the oxides of vanadium and manganese of the slag phase increases, which, in turn, is a necessary prerequisite for the rapid and complete completion of the reduction processes in the molten bath. As a result, the loss of alloying elements is reduced and the mechanical and service characteristics of the steel are increased. The duration of melting and the consumption of electric energy remain at the same level.

The introduction of lime or lime in the amount of less than 35% into the slag-forming mixture leads to insufficient liquid mobility and homogeneity of the furnace slag, as a result of which the kinetic conditions for the reduction of vanadium and manganese from oxides deteriorate (the content of the latter in the final slag is high). With an increase in the amount of lime or lime more than 45%, the dissolution of lime slows down, and the loss of alloying elements and. service properties of steel do not change significantly,

The lower limit of the alumina content of 10% is determined by the minimum value at which one hundred

five

five

5 o

. S 0 5

0

The noticeable effect of the composition on the rate of slag formation and the process of reducing vanadium and manganese is noticeable.

The upper limit of the alumina content is limited to 20%, the excess of which is not accompanied by a simultaneous decrease in the content of dopant oxides in the slag and an improvement in the service properties of the steel, therefore a further increase in its content in the mixture is impractical.

To confirm the optimality of the composition of the proposed mixture, a series of 10 pilot melts was conducted in a 5 ton electric arc furnace with a base lining.

The results of experimental floating are given in table. 1 and 2,

Smelting of steel is carried out by the method of remelting waste without oxidizing impurities. It is alloyed: the steel of vanadium is carried out using standard technology. The conditions of the test and the compared heats do not differ as. in terms of the quantity and quality of the metal charge, ferroalloys, as well as the duration of smelting and cost of electrical zinc. In the known bottoms, a mixture of lime or limestone and metal sifting is introduced into the filling in the ratio of 10: 4-10; 7, and the vanadium metagraphic mixture is calculated on the basis of 70 kg / ton of steel. In the experimental melts, the slag-forming mixture is given in a ratio of 34-46% lime or limestone 39-51% vanadium metal extract, 9-21% alumina.

The further course of steel smelting includes melting, finishing by chemical composition and temperature, sampling of metal and slag, and the release of metal into the ladle.

Additive in It was formed: a mixture of alumina in the range from 10 to 20% leads to a faster form of low-melting, homogeneous slag, an improvement in the kinetics of vanadium and manganese recovery, as a result of which the service properties of steel grow,

It has been established (Tables 1 and 2) that the introduction of alumina is within 10–. 20% with the same number of metal earthing and ferromanganese smelting leads to a higher degree of vanadium and manganese transition from furnace slag to metal. This is reflected in the content of vanadium oxides and the metal grade. Maximum mechanical properties (temporary resistance, plastic characteristics, impact strength) fall on the interval

alumina concentrations from 10 to 20%. These values correspond to the increased wear resistance of the steel.

The use of the proposed mixture allows to reduce the consumption of expensive doped ferroalloys due to a higher degree of extraction of vanadium and manganese, and also to achieve

689

20.3

Slag-forming mixture for steel alloying, containing lime or limestone and vanadium metal extractor, characterized in that, in order to reduce the loss of alloying elements and improve the service properties of steel, it additionally contains alumina or corundum-containing waste, with the following ratio of components., Wt. %: Vanadium metal extractor40-50 Lime or

27.7 2.61

104

Resume Table 2

Claims (1)

SUMMARY OF THE INVENTION A slag-forming mixture for alloying steel containing lime or limestone and a vanadium metal screen, characterized in that, in order to reduce the loss of alloying elements and improve the service properties of steel, it additionally contains alumina or corundum-containing waste, in the following ratio, wt.%: Vanadium metal lootsev 40-50 Lime or limestone 35-45 Alumina 10-20 Table! Mixture The components of the mixture, Z The chemical composition of the slag MAO "% Degree of assimilation  - Ζ Metal screening Lime or limestone Alumina CaO MgO Number 10 Al Λ Sloj ^V i ° j FeO, P, 0 _& And dr. V Mp Famous 70 thirty - 21 / 15.3 23,2 3.0 35, 7 0.28 The rest I 86.2 96.4 Proposed • 1 51 34 fifteen 24.2 14.8 18.8 3.3 33.4 0.22 Also 87.5 97.0 2 fifty 35 fifteen 29.0 14.2 16.1 8.9 31, 5 0.15 89.0 98.0 3 45 4p ' fifteen 34.6 13.9 11,4 9.1 zo. 8 0,11 92.3 98.7 4 40 45 fifteen 40.5 13.6 6.3 9.3 thirty, 2,09 92.8 98.9 5 39 46 fifteen 42.8 12, 5.9 8.8 29, 5.09 Rest 85.8 96.8 6 45 46 9 27, 14.6 18,4 6.5 32, 3.0.20 - 87.1 97.3 7 45 45 10 29, 13,2 17.0 8.2 32, 2 0.19 87.4 97.7 8 45 35 20 38, ί 12.9 7.5 9.7 31, 1 0.07 93.1 99,2 . 9 45 34 21 38, g 13, 7.8 10.6 thirty, 5 0,07 86.0 96.2 Table 2 Mixture Tensile Strength 0th. MPa Relative extension % Relative narrowing Ψ,% Viscosity KCV, MJ / m ² Relative wear resistance, % 1 1 3 4 5 ε Known 698 21.9 31.4 2.70 100.0 Proposed 689 20.3 27.7 2.61 104 Continuation of Table 2 1 g 3 4 5 6 2 723 24.3 33.9 2.96 107 3 784 27.3 36,4 3.24 ¹¹² 4 771 28.1 37,2 3.41 1 10 5 681 20,4 27.0 2.48 96 6 725 21,2 29.0 2,55 104 7 770 28.5 26.0 • 3.20 111 8 791 28.1 37.5 3.46 114 9 687 20.5 26.9 2,55 99