SU954171A1 - Method of extrafurnace treatment of steel - Google Patents

Description

one

The invention relates to the metallurgy of dimensional metals, and more specifically to methods of after-furnace processing of steel in a steel-casting ladle during the production of metal in a steel-making unit.

The use of a ishak-forming mixture containing slag manganese silicosis is known to increase the efficiency of steel refining and to improve the quality of metal I.

However, using this technical solution, it is impossible to achieve a significant increase in the efficiency of the method — a significant reduction in the dispersion of ferroalloys, an increase in the quality of steel. This is due to the fact that when using the method of refining steel in a ladle with a slag-forming mixture: it is not possible to increase the positive effect of each of the components of the mixture

The closest in technical essence is the method of extra-furnace

treating steel in a ladle using slag from the production of carbon ferromanganese and / or slag from the production of silicomanganese for megurulgium.

Using these slags in the implementation of the method, it became possible to reduce (up to 15 on a boiling and semi-quiescent metal) consumption of basic ferroalloys (ferromanganese, silicomanganese), the method has significant drawbacks in evaluating its use for significant savings: ferroalloys and improve the quality of the metal. This is expressed in a limited amount of slag (waste) from ferroalloy production, which provides savings for basic ferroalloys.

up to 5%.

The disadvantages of curbing include a relatively high content of non-metallic inclusions (total content of 0.0085-0.0095), since in this case there is practically no desulfurization of metal and the content of sulfide inclusions remains at the level of 0.0025-0.

The purpose of the invention is to increase the saving of ferroalloys and improve the quality of steel.

The goal is achieved by the fact that in a known method, which includes treating steel in a ladle with slag from carbonaceous ferromanganese production and / or slag from silicomanganese production, slag from carbonaceous ferromanganese, ca and / or slag production from co-manganese silicon is introduced into the ladle when 1 / 6-1L of its height, and then lime containing components are added to the metal stream, the additive of which is finished before the addition of deoxidation and / or alloying

The proposed technical solution is possible to implement in the production of various grades of steel smelted in any steel-smelting unit open-hearth furnace, converter, electric furnace). The materials used when using the proposed method must meet the requirements of technical specifications for chemical and fractional composition, according to storage conditions (moisture ingress is not allowed). Before releasing the melt from the steel melting unit, the metal temperature should be closer to the upper limit.

The method is determined in the production of semi-quiescent steel. The steel was smelted in Yur-ton open-hearth furnaces operating on a coke-domain mixture with oxygen input (up to 2000 MV4) for intensification of the process.

Before discharging the melt from the furnace, it is characterized by the following parameters:

Metal temperature

before deoxidation ;;,

eat, ®С1600-1620

Oxide content

iron in the slag (in

in terms of FeO), 10-12

The content of residual manganese in megatall,% .0,10-0, And

Untouched metal released

from the furnace, 100-ton steel-pouring ladles, when filled with koto (shx 1 / 6-1 / 4 of their height, onto the metal stream from the lrdochka, having a hingedly movable (in the middle part) metal partition, slag was introduced from an electric bridge pouring tap production of carbon ferromanganese or silico manganese (10-12 kg / t) (/ Then, as the first part of the boat was released, another compartment was opened (spontaneously under the weight of the contents) and freshly calcined lime was added to the metal stream (7-10 kg / t) 85). (After the addition of izde (the filling level of the ladle metal 2/5 of its height), the missing amount of deoxidizing agents (silicomanganese) was introduced into the kosh,

The waste used has a chemical composition given in Tables 1 and 2,

T a b l and c a 1 Slag from the production of carbon

ferromanganese

t .--

Table 2. Slag from the production of silico-manganese

Content%

tf6-52

10-17 16-22

0.02

The proposed method produced 6 strips (ladles) of steel.

The results of testing method 5 are given in table. 3

to

J s c

Yu (D

"

s

X

t

t

V

z s o.

7

Analysis of the results of testing the method shows that the use of the proposed technical solution ensures a reduction in the consumption of basic ferroalloys up to 27% (by a known method up to 15%), an improvement in the quality of steel by reducing the total content of non-metallic inclusions to 0.00b | (by a known method to 0,), including

sulphide up to 0,0013 (according to a known method up to 0,0025). Taking into account the cost of slag from carbon production of ferromanganese carbon 1.83 rubles / ton and lime 9 rubles / ton.

The economic effect from the application of the proposed method will be 0.7-0.9 rubles / ton of steel.

Claims (1)

1. USSR author's certificate No. 775J, kp. C, 21 C 13/00, 1979. 2, Specifications TU-N-11124-76.