SU1693077A1 - Method of melting steel and alloys - Google Patents

Abstract

This invention relates to ferrous metallurgy, in particular, to methods for smelting steel and alloys. The goal is to increase the absorption of alloying elements and reduce the duration of melting. A mixture of coke and high-silicon silicon manganese powder in a ratio by weight of 60: (0.3-1, 0) is placed on the slag before the metal is supplied with oxygen before the metal is blown into the slag. There is an increase in the absorption of chromium by 0.5-1.6% and a decrease in the duration of melting by 7-21 minutes. 1 tab

Description

The invention relates to ferrous metallurgy, in particular, to methods for smelting steel and alloys in a furnace or an afterburner.

The aim of the invention is to increase the absorption of alloying elements and reduce the duration of melting.

The high silicon silicate used has a composition,%:

Manganese

Silicon

Carbon

Phosphorus

Iron and impurities

45-60

30-45

0.06-0.20

0.08-0.30

Rest

High-silica manganese is a self-dissolving alloy, which eliminates the crushing or spraying operation when used as catalysts for cast iron and steel.

High silicon manganese reduces the wetting angle of chromium-containing and manganese-containing slag melts at the boundary with coke from 55-70 to 5-18 ° C and thereby increasing the adhesion of slag melts to coke by 25%. This provides an increase in the contact surface of coke with a slag melt, reduces the duration of melting and increases the absorption of alloying elements.

In the coal-thermal reduction of alloying elements from slag, where coke is used as a carbon-containing material, the degree of reduction of elements over a certain period of time, all other conditions being equal (furnace temperature, the amount of carbon-containing material located on the slag)

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contact surface of carbon-containing material with slag. The latter is determined by the adhesion of the slag to the coke.

The adhesion or adhesion work is determined from the equation A Stm (1 + cos #), where OM is the surface tension of the slag; c - wetting angle. For a given slag composition, the adhesion work is determined by the wetting angle. At a wetting angle of 180 °, the work of adhesion is zero, with a wetting angle of 0 °, the work of adhesion is maximum and equal to 26.

The absorption of alloying elements occurs due to an increase in the adhesion (adhesion work) of slag melts to coke, which leads to an increase in the contact surface of coke with the slag melt. In the first approximation, it can be said that the contact surface is proportional to the adhesion of the slag to the coke or is inversely proportional to the magnitude of the wetting angle, i.e.

S-K - J.

where S is the contact surface;

K is a coefficient proportional to the density and viscosity of the slag melt;

in - wetting angle.

With the proposed method, the contact angle of slag at the boundary with coke is reduced from 55-70 (prototype) to 5-18 °.

The use of a mixture of coke and a powder of silicon manganese eliminates the crushing of the metal phase and thereby reduces the laboriousness of the preparation of the mixture, shortens the duration of smelting and increases the absorption of the alloying elements.

The ratio of the mass of coke to the mass of high-silicon silicomanganese is established empirically. The upper limit (60: 0.3) limits the area of a sharp increase in the wetting angle of slag melts at the boundary with coke. At a ratio above the upper limit, the adhesion of the slag melts to the coke decreases, which leads to

to reduce the contact surface of coke with slag, increases the duration of smelting, reduces the absorption of elements. The lower limit (60: 1) is due higher.

Because of the cost, since with a ratio of less than 60: 1, the wetting angles are virtually unchanged, and the cost of the mixture increases due to a larger proportion of high silicon silicon.

PRI me R. Coke was mixed with high-silica manganese powder having the following composition, wt.%: Silicon 41.2

Manganese54,6

Phosphorus 0.15

Carbon 0.11

Iron and impurities. The rest in the mass ratio of 60: (0.2-2.0) was set down before blowing the metal with oxygen into an arc furnace with a capacity of 100 tons, in which steel 12X18H10T was produced. For comparison, melting was carried out according to the method prototype. A mixture of coke and metal powder (cast iron) in a ratio of 15: 1 was seated in a furnace before blowing metal with oxygen. The refining period was the same.

Indicators of heats are shown in the table.

As follows or obtained results, the proposed method allows to increase the absorption of chromium by 0.5-1.6% and reduce the duration of melting by 7-21 minutes.

Claims (1)

Invention Formula A method for the production of steels and alloys, which includes an additive to a furnace or a secondary furnace unit of a mixture of coke and a metallic material on the slag before oxygen blowing, characterized in that increase the absorption of doping elements and reduce the duration of melting; high-silicon manganese powder is used as a metal material with a ratio of the mass of coke to the mass of powder60: (0.3-1.0).