SU1229231A1 - Method of producing rimming steel - Google Patents

Description

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The invention relates to ferrous metallurgy, in particular, to the production of boiling steel for sheet metal with a carbon content of 0.05-0.08%, cast into ingots.

The purpose of the invention is to reduce the head trim and increase the ductility of the metal.

The essence of the method consists in pulling out the optimal chemical composition of the boiling metal with the minimum content of non-metallic inclusions and a uniform bucket in height, providing an intense boiling of the metal during casting and, as a result, sufficiently deep barking of the honeycomb bubbles. This is achieved by obtaining optimal carbon and manganese content of the steel.

 After steel deoxidation on the top and purging with a neutral gas in the metal, the sum of the doubled carbon and manganese content () should be in the range of 0.44-0.50%. If this amount, 44%, increases the amount of gusting during the rolling of tin due to the presence of RN H, which is associated with the damage of the ingot crust by the canaliculi and the presence of corundum in the composition of the inclusions, as in this case, the quantity of apyumini is introduced into the ladle to control oxidation. With an increase in this amount of 0.50%, especially with a content of 0.05-0.06% carbon, aluminum is not required to control the oxidation of the steel in the ladle, since manganese determines the oxidation of the metal in the molds. In this case, the boiling becomes limp, the growth of ingots is more than 150-200 mm, the increased cutting of the metal during rolling on slabing. When metal with low ductility is pro- cessed, the number of breaks increases.

Then a metal sample is taken and the oxygen activity is determined therein, subsequently maintaining the product of the carbon content in the metal for oxygen activity (O.) equal to 0.0032-0.0038% by means of deoxidizing additives.

When c; cx, 0.0032% get in the metal boiling boil, increases the expenditure ratio and the number of gusts during the rolling of tin. With c 0.0038% occurs, bor 292312

boiling of metal in the molds, which requires the addition of aluminum to the molds, as a result of which the metal contamination increases with complex oxide compounds and the number of gusts increases.

In tab. Figure 1 shows the effect of metal oxidation, in the ladle, on quality indicators.

Table}

0.0031 4.7

0,0032- 0,0038

12.1

+ 190

- (- 55

0,0039 Koroch- -75 ka pro-

Eshzapa Kienaltsami

1,22 0,0t8

1.18 0.003 1.32 0.012

In tab. Table 2 shows the effect of the SMP1 sum on the quality indicators. Table 2

0, Crust -65 0.396 pron35. zana

t, 29 0.013

channel "atoi

Since the determination of the oxygen activity in the metal is carried out

The possibility of taking a sample not from the melting unit, but from a coke after the metal is purged with a neutral gas, quickly appears. At the same time, the accuracy of the analysis is estimated and it is possible to promptly adjust the manganese content and metal oxidation with the minimum consumption of deoxidizing agents according to the specific data of the analysis, and not according to the calculated

as is the case in the known method, where the analysis of the oxygen content in a sample taken from the melting unit is carried out.

3

Example 1. Steel is melted in a 315 ton converter. Before release from the converter, the metal contains 0.03% of Cu 0,. In the process of steel production, 1,700 kg, ferromanganese, 50 kg of coke and 8 kg of aluminum are placed in the ladle. The converter slag is cut off and the refining mixture is placed in the ladle. After 2 minutes of purging with an inert gas in the ladle, a sample is taken and the oxygen activity and the temperature of the metal are measured. Get 0.05% carbon, 0.31% manganese,

 0.068%. In addition, 150 kg of ferromanganese, 12 kg of aluminum are added to the ladle and received 0.05% of carbon, 0.34% of manganese .- b, 44%) CESS - 0.0 0.0038%.

Example 2. Before release from a horse cooler, the metal contains 0.05% C and 0.07% Mn. In the ladle during the smelting process, 1600 kg of ferromanganese are sown and after a 3-minute purge in the ladle with an inert gas, 0.08% С, 0.34% Mr are obtained, with а „0.048%. 6 kg of aluminum is placed in the ladle and blown additionally for 5 minutes. 0.08% C, 0.32% Mb (, 48%) are obtained with, 0.0032%.

Example 3. Before release from the converter, the metal contains 0.04% C and 0 ,,. In the ladle, during the smelting-in process, 1650 kg of ferromanganese and 5 kg of aluminum are planted and, after a 2-minute purge with inert gas, 0.07% of C is obtained in the ladle 0.32% M h at 1 o 0.055%. During the purging process, 150 kg of ferromanganese are placed in the ladle and 8 kg of aluminum are introduced in the form of a wire to obtain Lo and

Editor V. Petrash

Compiled by O. Veretennikov

Tehred N. Bonkapo Proofreader T. Kolb

Order 2419/22

Circulation 552Subscribe

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

292314

 0.0035%. Get in the bucket sample 0.07% C, 0.36% Mn (0.50%).

 Example 4. Before release from the converter, the metal contains O, 06% C 5 and 0.10% M | -,. 1650 kg of ferromanganese and 5 kg of aluminum are squeezed into the ladle in the course of release, and the slag is cut out with a cut-off. After a 2-minute purge with an inert gas 10, 0.09% C, 0.38% Mn and

about 0.032%. 300 kg of scale are placed in a ladle and rinsed with an inert gas for 6 minutes. After purging, 0.08% C, 0.34% Mk and LC a are obtained, 15 0.0032%.

The head trim in examples 1-4 is 8.3; 7.8; 8.2 and 7.9%, and the number of gusts is 0.005; 0,004, 0,001 and 0,002 pcs. accordingly, i.e. significantly lower than by a known method (Table 3).

; Table 3

20

25

thirty

35

40

Economic efficiency is determined by metal savings and reduced downtime of the rolling mill.

Claims (1)

METHOD FOR PRODUCING BOILING STEEL, including its smelting in a steelmaking unit, determination of chemical composition, deoxidation of metal in a ladle and casting, characterized in that, in order to reduce head cut and increase the ductility of the metal, it is purged with neutral gas after it is released into the ladle and regulate the activity oxygen by the addition of deoxidizing agents, maintaining the product of carbon and oxygen activity in the metal equal to 0.00320.0038%. S