SU1756366A1 - Process for producing corrosion-resistant steel - Google Patents

Abstract

Essence: on the proposed method of smelting corrosion-resistant steel with a carbon content of not more than 0.05%, which includes smelting the intermediate in an arc furnace, pouring the melt into the refining bucket, blowing it under vacuum with oxygen from the top and argon from the bottom, melting the melt and adjusting the composition, blowing it the melt conducts in two stages, the first of which is ri ri / Ki / Qf-Ka for where the initial carbon content is. melt,%; Q — oxygen consumption, m3 / (min-t); Ki 9-10 m3 / t; K2 10-11 min - empirical coefficients, oxygen is supplied to the melt with a flow rate of 0.6-0.8 m3 / (min-t) with mixing power due to purging with argon 0.65-1.0 W / t, and in the second stage duration Kz ln (Q) + Kz, where - given the final carbon content,%, Kz-1.1-1.3 t / m3, K / | 9–11 min are empirical coefficients; oxygen is supplied to the melt at a rate of 0.4–0.5 m / (min – t) at a stirring power due to the argon loading of 1.35–1.65 W / t. i

Description

The invention relates to the field of metallurgy and can be used mainly in the production of steel alloyed with chromium containing not more than 0.05% carbon.

There is a known method of steel smelting, which includes melting the floor of a product in an arc furnace, pouring the melt into the refining bucket, evacuating for ten minutes while simultaneously purging with argon (consumption 0.007-0.014 m3 / (min-t)), while the melt mixing power due to Argon purge is 6.2-12.4 kW / t, the composition adjustment.

The known method does not provide a low carbon content (not more than 0.05%). There is also known a method of smelting corrosion-resistant steel, which includes smelting the intermediate product in an arc furnace, pouring the melt into the refining bucket, simultaneous vacuuming and blowing oxygen from the top (flow rate 0.24-0.57 m / (min)) and argon bottom (flow rate 0.00057-0.0007 m3 / (min-t)) for 30 min, while the melt mixing power due to argon purge is 0.69 W / t, simultaneous evacuation with argon purge for 10

about

Och

PH &

mines, melt and slag deoxidation, composition adjustment.

The disadvantages of this method are its considerable duration, which reduces the productivity of the unit, as well as increased chromium loss, which increases the cost of steel.

The purpose of the invention is to reduce the duration of the process while reducing the cost of steel by reducing chromium carbon.

In order to achieve this goal, in the method of smelting corrosion-resistant steel, including smelting the intermediate product in an arc furnace, pouring the melt into the refining bucket, blowing it under vacuum with oxygen from above and argon from the bottom, deoxidizing the melt and adjusting the composition, blowing the melt is performed in two stages: the first of which lasting

 - + K2,

(one)

where - the initial carbon content in the melt,%;

Q — oxygen consumption, m / (min t);

KI 9-10; K2 10-11 - empirical coefficients,

oxygen is fed into the melt with a flow rate of 0.6-0.8 m3 / (min t) with a stirring power due to an argon purge of 0.65-1.0 W / t, and in the second stage with a duration of

T2 Кз -in {Q- C k} -t-K4, (2)

where - given the final carbon content,%;

Кз 1,1-1, Зт / м, К4 9-11 min-empirical coefficients, oxygen is supplied to the melt with a flow rate of 0.4-0.5 m / (mint) with stirring power due to argon blowing 1.35- 1.65 W / T

Carrying out the purge in two stages, the duration of which is determined by expressions (1) and (2), while ensuring oxygen consumption and mixing power due to purging with argon within the above limits, reduces the loss of chromium from the slag, shortens the processing time of the melt due to the creation of optimal hydrodynamic situations in the bucket.

In the case when the duration of the purge is shorter than that calculated by equations (1.2), the specified carbon content (no more than 0.05%) is not reached, and in the case of a large amount, the loss of chromium with slag increases.

Purging the melt with oxygen at a rate of more than 0.8 m3 / (min-t) in the first stage and 0.5 m3 / (min-t) in the second stage also leads to an increase in chromium loss. Purging with an oxygen consumption less than 0.6 and 0.4 m / (min-t) at the first and second stages, respectively, entails an increase in the duration of the process.

Providing a stirring power due to an argon purge lower than 0.65 W / t and 1.35 W / t for the first and second stages, respectively, leads to an increase in chromium loss. In case the stirring power due to argon purge exceeds 1.0 W / t at the first stage and 1.65 W / t at the second, metal emissions from the ladle are possible, which entails welding the lid to the ladle,

The proposed method is carried out as follows.

At the out-of-furnace refining and steel degassing installation (UVRV-1), the semi-finished steel OOH18N10 was treated

weighing 500 kg, smelted in an arc furnace containing 0.2-0.6% carbon, 17-18% chromium, 9-10% nickel, 0.1-0.4% silicon, 0.2-0.8% manganese. After the metal was heated, the temperature was measured and sampled.

samples. Further, knowing the initial carbon content, the mass of the melt, the required final carbon content, and choosing, based on the specific melting conditions, the oxygen consumption, by expressions (1) and (2) are determined

the duration of the first and second stages of the purge. Knowing the heat of melting, the temperature of the metal before the treatment, the argon flow rate, which is necessary to ensure the specified mixing power, was determined:

0i044-T-V-tn ().

where Ј is the stirring power due to purging with argon, W / t; V - argon consumption, m3 / (min t); T is the initial temperature, K; h is the height of the metal column, m; Ro is the residual pressure above the melt, hPa.

Having determined the flow rate of argon, the pressure above the melt was reduced to 530 kPa, and simultaneously with a decrease in pressure, oxygen and argon flushing began. After some time, the consumption of oxygen and argon was changed, the purge was terminated, the vacuum was removed, and the composition was deoxidized.

With an initial carbon concentration of 0.42% and an oxygen consumption of 0.7 m3 / (min t), the duration of the first stage was

, and 0.42 ,,

ri-9 oT + 11

16.4 minutes

Argon consumption in the first stage at an initial temperature of 1873 K, residual

pressure of 530 kPa and a selected stirring power of 0.75 W / t was

0.75

V

0.044-1873 ln (1 -F -58

0.4

0.053) 0.00089 m3 / (min t),

The duration of the second stage with a given final carbon concentration of 0.03% and oxygen consumption of 0.4 m3 / t min was

G2 C In (0.4-0.03) + 10 5.13 min.

The flow rate of argon in the second stage of the purge with the selected mixing power of 1.5 W / t and a residual pressure of 0.05 atm was

1.5

V

0.444873ln (1 + Sn # l)

0.053 0.0018 m3 / (min g) The test results are shown in Table. As can be seen from the table on smelting No. 1, an increased final concentration of carbon is obtained due to the fact that the processing time is shorter than that calculated by equations (1) and (2) On smelting No. 2, an increased loss of chromium was observed, as well as a longer processing time, due to that the processing time is longer than that calculated by equations (1) and (2). At smelting No. 3, an increased chromium frenzy was observed due to the fact that oxygen consumption was higher than recommended. In smelting No. 4, a high final carbon content was obtained due to the fact that oxygen consumption for the calculated treatment duration was lower than recommended. In smelting No. 5, high chromium loss was due to the fact that for such a large oxygen consumption, the mixing power due to argon purging was lower than recommended. On smelting number 6 occurred

Technological characteristics and results of corrosion-resistant steel

dangerous splashes of metal from the bucket, due to too much of the mixing power. The use of the proposed technical solution (melting No. 7-9) makes it possible to reduce the loss of chromium, to reduce the duration of treatment as compared with prototype SHG.

ten

15

0)

Formupe of the Invention A method of melting corrosion-resistant steel, which includes smelting the intermediate product in an arc furnace, pouring the melt into the refining bucket, blowing it under vacuum with oxygen from above and argon from the bottom, deoxidizing the melt and adjusting the composition, which is designed to reduce the duration of the process while reducing the cost of steel by reducing chromium carbon monoxide, the melt blowing is carried out in two stages, the first of which is

 + K2,

where is the initial carbon concentration,%;

Q — oxygen consumption, m / (min t);

Ki 9-10 m3 / t; "2 10-11 min., - empirical coefficients, oxygen is supplied to the melt with a flow rate of 0.6-0.8 m3 / (min. T), and the mixing power due to purging with argon is 0.65-1.0 W / t. , and at the second stage lasting:

G2 K3-ln () + K4, (2)

where the specified final carbon content,%;

Cs 1.1-1.3 t / m3, "4 9-11 min-empirical coefficients, oxygen is supplied to the melt with a flow rate of 0.4-0.5 m / min, and the stirring power due to purging with argon is 1, 35-1.65 W / t. 0

smelting process tests

0

five

0

five

Table continuation

Proposed

1 2 3 it 5 6 7 8 9

O, 0.0006) 0.69 0.026 1873

thirty

Claims (1)

Claim Method Smelting of corrosion-resistant 10 steel, including smelting the intermediate in an arc furnace, pouring the melt into a refining ladle, blowing it under vacuum with oxygen from above and argon from below, deoxidizing the melt and adjusting the composition, characterized in that, in order to reduce the duration of the process while reducing the cost of steel by reducing the loss of chromium, the melt is purged in two stages, the first of which lasts η = К1 · Ι ^ + κ ₂ , (1) where (С] n is the initial carbon concentration,%: Q — oxygen consumption, m ³ / (min · t); Κι = 9-10 m ³ / t; To ₂ = 10-11 min, are empirical coefficients, oxygen is supplied to the melt with a flow rate of 0.6-0.8 m ³ / (min · t), and the mixing power sz due to purge? Ki argon is 0.65-1.0 W / t, and in the second stage, the duration: T2 = Kz * 1r> (Q · [C] k) + Kd, (2) where [C] k is the specified final carbon content,%: KZ = 1.1-1.3 t / m ³ , K4 = 9-11 min - empirical coefficients, oxygen is supplied to the melt with a flow rate of 0.4-0.5 m ³ / min, and the mixing power due to argon purge is 1.35-1.65 W / t. smelting test method Way you- Initial Ultimate Duration Consumption Consumption Power Duration Consumption swimming trunks steel concentration conc'ent nost sour argon shifting nost sour carbon dioxide walkie-talkie the first kind on on the front sewing second kind kind,% Leroda,% period first out on the front stage on the second MIN stage stage eo this- min this rum __________ ME / T’MIN m ³ / t min ______...... ne, W / t ne, m ³ / min T- ( Prototype 0.5 0.01 - ·. - - - - Proposed 1 0.5 0,07 fifteen 0.8 0.001 0.83 5 0.5 2 oh 4 0,03 20 0.7 . .0,001 0.83 10 0.5 ’3 0.4 0,03 fifteen 0.9 0.001 0.83 5 . 0.7 4 0.3 0,07 16 0.5 -0.001 0.83 6 0.3 5 0.3 0,03 18 0.7 0,0005 0.41 6 0.5 6 0.3 0,03 18 0.7 0.0015 1.25 6 0.5 7 0.5 0.02 16. 0.6 0,0008 0.67 4 0.4. 8 0.5 0,03 17 0.8 0.0012 1,0 5 0.5 9 0.5 0,03 17 0.7 0.001 0.83 5 0.45 Ί Table continuation Steel smelting method Argon consumption in the second stage, m ^e / min t Mixing power in the second stage, W / T Average oxygen consumption, m ³ / min t ......... AVERAGE argon consumption m ³ / min t Average mixing power W / T Pressure over the melt, hPa Initial metal temperature, K Processing time, min Ϊ Loss of chromium,% 7 Prototype - 0.4 0,00064 0.69 0,026 1873 thirty 2 ] Proposed ί 1 0.002 1.66 0.73 0.0013 1,03 0.05 1873 20 0.9 ! '' '2 0.002 1.66 0.64 0.0013 1.10 0.05 1883 30 2.2 3 0.002 1.66 0.88 0.0013 1,03 0.05 1873 20 2.1 ί h 0.002 1.66 0.45 0.0013 1.06 0.05 1863 22 0.8 5 0.001 0.83 0.65 0,0006 0.52 0.05 1873 24 2 !, 3 6 0.003 3.0 0.65 0.0018 0.05 1893 1893 24 1 0 7 0.0016 1.35 0.56 0,0009 0.84 0.05 1973 20 C ,8 8 0.002 1.65 0.73 0.0013 1.15 0.05 1883 22 1 0 9 0.0018 1,5 0.64 0.0012 0.98 0.05 1873 22 1 ,1 Make-up gel D. Sidorenko Editor L. Volkova Tehred M. Morgenthal Corrector L. Gereshi Order 3063 Circulation Subscription VNIIIPI State Committee for Inventions and Discoveries under the State Committee for Science and Technology of the USSR 113035, Moscow. Zh-35, Raushskaya nab., 4/5 Production and Publishing Plant Patent, Uzhhorod, Gagarin str. / 101