SU1514797A1 - Method of producing steel - Google Patents

Description

The invention relates to metallurgy, and in particular to methods of increasing the service life of bottom tuyeres for supplying mixing gas to converters of the combined blast. The purpose of the invention is to increase productivity by increasing the durability of the tuyeres and reducing the consumption of the refractory lining of the bottom. It is up to DlM that the humidity of the stirring gas is carried out depending on the degree of wear of the bottom tuyeres, and with a degree of wear of 5 to 15% relative humidity

“hectare” is maintained at a level of 25–40%, with a degree of wear of 16–30%; on

level 41 --- 60%, with a degree of wear 3! 45% ', at the level of 61 95% ,. I tabl

The invention relates to metallurgy and can be used in the converters of the combi by another blow.

The purpose of the invention is to increase productivity by increasing the resistance of the tuyeres, reducing the consumption of the refractory lining of the bottom.

The essence of the method is to create a controlled process of heat absorption by slag from the mixing gas, depending on the degree of wear of bottom tuyeres, creating slag skull with directional channels of outflow, ensuring high values of throughput of bottom tuyeres during the campaign.

During the steelmaking campaign in the converter, there is a significant increase in bottom tuyeres, even during one melt, both as a result of thermal stresses and as a result of erosion of the near-turf zone.

With a joint wager ;; and mixing gas it is possible to provide regulation of the gene process. ιοπηι polishing. thus avoiding sharp thermal shocks in the near-persimn zone. In addition, when a wet gas passes through the slag, the channels of gas outflow from the tuyere are created in the latter, since the wet gas has a continuity. The change in the relative humidity of the supplied gas allows, depending on the height of the farms, to ensure a minimum time for slagging them.

In the process of research

found to be relative humidity

should be changed according to degree

lance wear and maintain at degree

wear 5--15% at the level of 25 40, with stebi ,, ,, 1514797

1514797

four

fines of wear 16–30% - at the level of 41 —60%

and with a degree of wear 31-45% - at the level of 61-95%.

The method is as follows.

The converter is equipped with a purge system with individual regulation for each bottom form of mixing gas flow (argon, nitrogen, compressed air). The system allows gas to be supplied to the bottom lances both separately and in a predetermined ratio. The frequency of nitrogen and argon is at least 98%. Compressed air has 100% humidity with a device in the pipeline to remove moisture condensate. Gas pressure not less than 1.0—1.2 MPa.

After the metal is released from the converter into the ladle, the wear condition of the bottom tuyeres is determined (visually or with the help of a measuring probe) and, if necessary, slagging of all or individual tuyeres is performed. To do this, the main part of the slag is poured into the bowl, and 2-3 tons of slag are left in the converter. The degree of wear of the tuyere set the ratio of the costs of nitrogen and compressed air supplied to the purge. The total gas flow rate for each of the tuyeres is determined by the diameter of the lance of the tuyere and the gas pressure. When using single-channel periclase-carbon blocks with an orifice diameter of 6 mm, the maximum flow rate of gases through one tuyere block is 2.0-2.5 nm ’/ min. The gas flow rate through the bottom tuyere when it is slagging is fixed.

After the end of the operation of slagging, slag in the converter is thickened with lime additive, is filled with scrap metal, cast iron is poured and oxygenated from above. The flow rate of the mixing gas through the bottom tuyeres is determined by the technological necessity of the process. The ratio of the costs of neutral gas and water vapor through the restored by the slag skull of the tuyeres during the purging with oxygen is maintained the same as when slagging them.

After 5-10 heats, the state of the tuyeres is checked and, in the absence of their noticeable

wear iodacha water vapor on the lance stops. Accordingly, when wear is increased on other lances, they are slagged.

Example. Testing the proposed method of protecting the bottom tuyeres produced on 160 tons of converters. The converters are equipped with a combined purge with oxygen from the top with an intensity of 500-600 nm ³ / min and a mixing gas from the bottom (nitrogen, argon, air) with a flow rate of 5-40 nm '/ min.

After the metal is released from the converter, the state of the bottom and bottom converter tuyeres is monitored and the tuyeres are slagged. The main liquid part of the slag is poured into the slag bowl and further steel production is effected according to the instructions in the workshop. Periclase-carbon blocks with an internal diameter of 6-7 mm are used as bottom tuyeres. The durability of the converter is estimated by the value of the bottom wear rate for smelting (mm / smelting), which makes it possible to determine the strength of the converter bottom, knowing the thickness of the bottom (920 mm). The results of the experimental heats are shown in the table.

Analysis of the experimental heats shows that the application of the proposed method allows to increase the production of steel, durability and reduce the consumption of the refractory lining of the bottom.

Claims (1)

Claim The method of steel production, including metal purging with oxygen, metal release, leaving slag in the converter, entering a wet mixing gas through wear tuyeres from below, characterized in that, in order to increase productivity by increasing the durability of tuyeres, reducing the consumption of the bottom refractory lining, the mixing gas humidity depending on the degree of wear of the tuyeres, the relative humidity of the mixing gas is maintained at a level of 25–40% with a degree of wear of 5–15%, and with a degree of wear of 16–30% and the level of 41-60%, while the degree of wear of 31 - 45% - at a level of 61-95%. 1514797 The results of the experimental converter (campaign) heats 6 №№ i / p Magnitude degrees wear, tuyere, Ζ Relative gas humidity, Ζ Gas flow through nm ³ / min 3 lance, Time slagging min Magnitude wear Furm, bottoms nm / melt Durability tuyeres, melts Nitrogen (argon) Compressed air Overall one five 25 1.0 oh w 1,3 3.1 0.34 882 2 ten thirty 0.9 0.4 1,3 3.2 0.35 857 3 15 40 0.8 0.5 1,3 3.2 0.37 81 1 four five 20 0.105 0.25 1,3 4.7 0.57 526 five ten 45 0.7 0.6 1,3 4.3 0.52 577 6 sixteen 41 0.8 0.5 1,3 3.4 0.37 81 1 7 25 50 0.65 0.65 1,3 3.5 0.38 789 eight thirty 60 0.5 0.8 1,3 3.6 0.39 768 9 17 thirty 0.9 0.4 1,3 4.8 0.54 556 ten 20 70 0.4 0.9 1,3 4.2 0.53 566 eleven 40 80 oh w 1.0 1,3 3.7 0.41 741 12 31 61 0.5 0.8 1,3 3.8 0.43 698 13 45 95 0.1 1.2 1,3 3.9 0.42 714 14 34 55 0.6 0.7 1,3 4.6 0.50 600 15 44 100 - 1,3 1,3 4.5 0.60 500 Prototype 51 1: 3 1,3 8.7 0.53 566 .. _____________________ ____________ _C1 | .---------, - t, —— Note: reduction in throughput of tuyeres by 25; 34; 31, 12> ..